Tonight, Nikki Haley vowing to stay in and fight on after Donald Trump's landslide victory in South Carolina. The former governor already campaigning in the next primary state after last night's historic defeat in her home state. Trump supporters calling on her to drop out, the mega donor group whose support she just lost. A man lights himself on fire outside the Israeli Embassy in Washington, as the US helps broker a possible new ceasefire in exchange for the release of Israeli hostages. Ukraine's President, Volodymyr Zelensky, one-on-one with our Richard Angle, his message to American lawmakers. What happens to your country if this American aid doesn't arrive? Another murder at a college, this one in Kentucky, the campus on lockdown, a fellow student arrested. It's the fourth high-profile campus murder this month. Are you ready for the spring, the Great American warmup? Who's about to get some record high temperatures? This is NBC Nightly News with Kate Snow. Good evening. The results of the South Carolina primary were not unexpected. Former President Donald Trump had a sizable lead in polls there. But a big question heading into Saturday's contest was, what would Nikki Haley do next? Well, now we have our answer.

The former governor of South Carolina is not dropping out, not backing down. This is a live look at an event she's about to hold right now in Michigan, which has its primary on Tuesday. Haley says she wants to give voters a choice in this election, but make no mistake, last night's loss was historic. She lost to Donald Trump by 20 points. The biggest primary loss by a candidate in their home state in modern times. This week, the Republican primary calendar kicks into high gear. Take a look at this. In the next 10 days, 19 states and Washington, DC will hold primaries and caucuses. In many of those states, it will be a lot harder for Haley to win any delegates. We begin tonight with Ali Vitale on the Trail with the Haley campaign. Tonight, Mickey Haley not backing down. I'm a woman of my word. I'm not giving up this fight Donald Trump's sole rival, sticking in the race, defiant. And barreling into Michigan, even after a historic loss in her home state of South Carolina last night. I'm grateful that today is not the end of our story. Trump, meanwhile, full steam ahead. An even bigger win than we anticipated.

Ignoring the primary and already wishing for the general election. In certain countries, you're allowed to call your election date. If I had the right to do it, I'd do it tomorrow. He's preparing the party for that, too. Seeking to install family members and allies to run the Republican National Committee. The next stretch of voting states looming large. Michigan, followed by Super Tuesday a week later. Most of those winner take all states, making it tough for Haley earn delegates unless she actually wins the state. Haley's campaign manager last night. I think the thing that we get hung up on, I think probably rightly so, is the delegate math. There are a lot of those states that are winner take all. There's also a lot of proportional states. We know the odds, but we also know the stakes. Haley hitting nearly a dozen states in the next 10 days and seeing reason to keep going. I know 40% is not 50%, but I also know 40% is not some tiny group. Even the unlikeliest of voices, like Democrat Gavin Newsom, urging Haley on. I hope she stays in, personally. And independent voters, even those who ultimately opted for Trump.

I think she should keep going. I think she's a smart woman, so I think she should stay in it and see what happens. Allie joins me now from a Haley rally in Michigan, and there are new obstacles for the Haley campaign. Yeah, that's exactly right, Kate. Even as the Haley campaign is touting a million dollars in just 24 hours since South Carolina. Nbc News has just confirmed that a major conservative group, aligned with mega donor Charles Koch, is pulling its support, including funding from the Haley campaign. They're sighting challenges in the states ahead as to why. Kate. Ali Batali for us. Ali, thank you. Overseas tonight, we're getting our first look at video of a new round of US airstrikes targeting terrorist weapon stockpiles in Yemen. It's the latest mission by the US to stop fighters from taking over ships at sea. Aaron Gilkrist reports. Tonight, new video of American fighter jets launching from the Red Sea, lighting up the Saturday night sky in Houthi-controlled Yemen. Us and British forces say they struck 18 Houthi targets, this time including underground weapons facilities. A fourth joint mission to stop attacks on military and commercial ships in and around the Red Sea.

The Iran-backed rebels, vowing to continue targeting ships they say are connected to Israel until it ends military action in Gaza. Israeli Prime Minister Benjamin Netanyahu on American television Sunday morning is promising only victory over Hamas will end the war. Unless we have total victory, we can't have peace. We can't leave Hamas in place. We can't leave a quarter of Hamas battalions in Raqqa and say, Well, that's fine. Netanyahu also confirming he's presenting his government an updated hostage release and ceasefire deal, brokered by the US, Egypt, and Qatar. Demonstrators demanding an end to the suffering. According to DC police, a man set himself on fire outside the Israeli embassy in Washington. Social media posts claim he yelled, Free Palestine. Meanwhile, demonstrators in Tel Aviv insisting more be done to return Israeli hostages home. Netanyahu is suggesting Hamas's demands still go too far. They're on another planet. But if they come down to a reasonable situation, then, yes, we'll have a hostage. Netanyahu is saying a deal would delay Israeli soldiers rolling into Rafeh, where more than a million displaced Palestinians have been forced into a small area, adding that before a major strike there, civilians would be evacuated back into parts of Gaza already destroyed.

Erin joins me now from the White House. Erin, is President Biden supporting the Rafeh evacuation plan you just mentioned? Well, Kate, the President's National Security Advisor says Israel needs to have a clear executable plan to protect and house Palestinian civilians before a major military operation in Raafa, adding that the White House has not seen a plan like that yet. Kate? Erin Gilkris for us. Erin, thank you. This weekend marks two years since Russia first invaded Ukraine. By most accounts, The tide has shifted in Russia's favor. Tonight, our Richard Engel sat down with Ukraine's President, Volodymyr Zelenskyy, who's desperately trying to reach an audience here in the US to convince the American public and Republican lawmakers his country is worth helping. As Ukraine commemorates two years since Vladimir Putin invaded, President Zelenskyy told reporters tonight, Delays of weapons and ammunition from allies, including the United States, are costing Ukrainian lives, saying 31,000 of his troops have been killed so far in the war. His first update of the death toll in a year. President Zelenskyy said, Russian troops are taking advantage of Ukraine's lack of supplies with a new offensive offensive, which he expects will intensify over the next two months.

I met up with the President. Hi. Good to see you again. Thank you very much. In our fifth conversation since the war began. The President began by saying Ukraine has no choice but to keep fighting because the cost of losing to President Putin is everything. If he will break defending lines, he will destroy all the cities. He doesn't need anything, any Ukrainian culture. He will destroy architecture, museums, schools, universities, people. Mr. President, I just returned from several areas along the front line in the south and in the east, and soldiers there told me they have to ration their ammunition. What happens to your country if this American aid doesn't arrive? We will lose a lot of people. We will lose territories. If to give us strong package in one time, our steps will be more strong on the battlefield. Do you think the United States wants Ukraine to win this war, or do they just want you to weaken Russia and contain Russia? I hope so. I hope so. Otherwise, how to trust people? It's so difficult to live without any trust. We count on our You said that you believe this year is a turning point year for Ukraine because of, in part, US elections.

You pointed specifically to the US elections. Are you talking about Donald Trump? Are you worried that Donald Trump could pull the plug? I hope he will not stop. If he will be the President, that is the decision of your people, of course. I hope that the policy of the country will not change. I count on the American people. President Zelenskyy also outlined a peace plan to end the war with Ukraine presenting its terms to Russia this spring, followed by direct talks. The Kremlin has already rejected the proposal. Kate. Richard Engel for us. Richard, thank you. Back in the US, there's been yet another murder on a college campus, the fourth high-profile killing in the last few weeks. While the crimes are unrelated, it's an alarming wake-up call about violence in what is supposed to be a safe place for students. Marissa Para has more. Tonight, a new murder charge in the latest case casting anxiety over yet another college campus. This time, Kentucky's Campbellsville University. Eighteen-year-old Josiah Kilman found dead in his dorm room yesterday, sending the campus into lockdown until 21-year-old Charles Escalera was found and arrested in a barn, both of them students, a cause of death not yet released.

This as we're learning new details over student killings in Colorado Springs. 26-year-old Sealy Montgomery and student 24-year-old Samuel Nopp gunned down over a week ago in a University of Colorado dorm room. Nopp's roommate, 25-year-old student, Nicholas Jordan, charged with two counts of first-degree murder. Newly unsealed documents show a history of tensions in the apartment. Following a January argument, Jordan threatened not that he would kill him, and there would be consequences if Mr. Jordan was asked to take out the trash again. I still feel really on edge. Meanwhile, University University of Georgia reeling after 22-year-old Laken Reilly was murdered while running on campus Thursday. 26-year-old Jose Antonio Ibarra, a non-US citizen from Venezuela, charged with her murder. Authorities say they didn't know each other. His brother, Diego Ibarra, charged with possessing a fake green card, together igniting a political firestorm among Conservatives like Georgia Governor Brian Kemp, demanding President Biden take federal action to secure the border in the wake of Reilly's death. You have people like these two individuals that came into the country and then committed crimes, and nobody was notified of those. And why were they not sent back? Meanwhile, a student-led petition has almost 25,000 signatures demanding the campus reinstall emergency blue lights, call boxes used to quickly alert authorities to someone in trouble as students grapple with trying to find safety and closure.

Marissa is with us from the University of Georgia, so students will return to class tomorrow? That's right, Kate. Their first since Thursday evening. Tomorrow will also mark the first campus vigil held in Reilly's honor. Kate. Marissa Par, thank you. We're back in a moment with the terrifying minutes just after a house explosion, all caught on police body cameras. Plus, the big winter warmup. Record temperatures could be ahead for millions. Just how hot will it get? If you're already sick of winter, you're in luck. Much of the country in for a potentially record breaking warmup. Temperatures are expected to soar across half the country starting tomorrow. We're talking about as high as 30 degrees above average in places, even getting into the '60s in New York, and nearly 70 in Chicago this week. Tonight, a new look at the terrifying moments following a house explosion in Michigan, all caught on police body cameras. Here's Maggie Vespa. Like something out of a disaster movie. When off, you Body camera video just released by Ann Arbor police gives a first-hand look at Monday morning's jaw-dropping home explosion that rocked this quiet Michigan neighborhood. What did you think when you saw how big this was?

Definitely was a surprise for me. I was really shocked. Oh, my God. There's been an explosion across the street. Beginning with 911 calls and dash cam video as police raced toward the scene, the nearly two-minute clip shows a neighbor blurred by police running toward Officer Zack Cunningham. Is anybody there? Do you know of? Somebody was in there and it looked like- The other officer very quickly found the man who they thought was inside. It turns out, thankfully, he wasn't. He was outside the home. Correct. I think Officer Betz was able to locate him within the first 30 to 60 seconds of us being on scene. Everybody back up. Officers scramble to clear the area. Moments later, the home completely caves in. There's a chimney. It's a brick chimney. The brick actually makes it all the way across the street into the neighbor's yard. Oh, it's scared of the living daylight on me. Our affiliate, WDIV, was there in the aftermath of Monday's fire as neighbors and the city's fire chief piece together what happened. We do have reports that propane was possibly being used inside of the house for heating. Investigators later confirming propane tanks caused the explosion, adding no other homes were damaged, and the man who lived there in his 70s was injured but survived.

He and his neighbors, now left with a terrifying story to tell, caught on camera. Maggie Vespa, thank you. When we come back, there's good news tonight about the life-saving bond that brought this teacher and student together. There's good news tonight about supporting each other through uncertain times, and the kindergarten teacher who's making sure one little girl knows she is not alone. Mad. Pad. At Lake Highland Preparatory School in Orlando. You have to think about this one. Kennedy Vaught and her kindergarten teacher, Carlene Honner, share a special bond. Once I met her, it was over. I was in love. I was excited to embark on this new journey of a new school year together. That journey includes something they have in common. Both are heart surgery survivors. Kennedy had hers at Advent Health less than a year ago.Thank you, guys. We have all set. So when it came time for her to start kindergarten, mom, Kristen, was overjoyed to discover Ms. Honor, knew just what Kennedy was going through. Oh, my gosh. I cry every time we talk about this. It's special to have this element to it When going into something we thought was so scary, we've come out of with nothing but Mrs.

Honour's words' blessings. I wanted to reassure Kennedy as well as her mother that she was going to be okay. She was going to be in great hands. All right. Mrs. Honor, who had her surgery five years ago, says she's teaching Kennedy that their scars are a sign of strength and courage. We just call each other heart twins. One of the things I wanted Kennedy to know was that the scar was a reminder, a blessing, and not to let it stop her from doing the things that she wanted to achieve. Can you do a split? Kennedy is now back doing gymnastics. Give me a A. And wants to be a cheerleader. Give me a T. We're walking for you, girl. And together, they teamed up for the Greater Orlando Heart Walk. For Ms. Honor, it was a powerful reminder about just how lucky she is to be alive. That was my moment that I had to I'm really proud of myself. That I realized I survived something greater than what it is. Gratitude for second chances and a new friendship that will last a lifetime. I always want you to know that Ms. Anna loves you this much.

I'm always going to be there to cheer you on. Just love that. That is NBC Nightly News for this Sunday. As I mentioned last week, this is my last Sunday with you, Anchoring Nightly News. But I'm not going far. You can watch me Monday through Friday on NBC News Daily from 2:00 to 04:00 PM Eastern Eastern Time. You can find me on your local NBC affiliate or on our streaming network, NBC News Now. I'll see you there tomorrow, and I'll keep reporting for Nightly News as well. Thank you so much for watching. For all of us here at NBC News, stay safe. Have a great night.. Thanks for watching. Stay updated about breaking news and top stories on the NBC News app or follow us on social media.