Former New Jersey Gov. Chris Christie fired back on calls from Gov. Chris Sununu to drop out of the race for president, telling WMUR in a one-on-one interview Tuesday that any suggestion that his campaign is on its last breath is simply false. "It pains me to say this, but Gov. Sununu is a liar," Christie said.During an appearance on CNN on Tuesday, Sununu suggested that there are ongoing discussions within Christie's campaign regarding whether to call it quits."I would say this, I think members of his leadership team here in New Hampshire are having those discussions with him and that's the right folks to do it there. He has no ground game. He's not even trying, even in the next two or three days, he could be here doing 10 events a day — he's doing like two," Sununu said. "There's no real emphasis of his own campaign here. He's running out of resources, he's not campaigning in any other state. I think those discussions are happening."When pressed about how he knew that these discussions were happening, Sununu said that he had discussions with members of Christie's steering committee, some of whom had already left."I think that's just the kind of the writing's on the wall because I'm talking to the folks on his steering committee and they're all saying the same thing," Sununu said. "I know a lot of those folks are having those conversations."Christie said that he spoke with members of his steering committee and that he is unaware of anyone who is having those conversations."He doesn't have to worry about the Christie campaign He's looking at the person who makes the decisions for the Christie campaign," Christie said.Christie called out Sununu, whom he said has not spoken to since the presidential debate in Alabama, adding that when Sununu endorsed former South Carolina Gov. Nikki Haley, he did not call him to let him know beforehand, and he learned about it on the WMUR website."I wasn't the one who went off on a fantasy trip to Iowa to pretend that I'm running for president when he didn't have the guts to do it himself," Christie added. "It's a shame to see Chris Sununu selling himself out. But if he wants to say something to me, he's got my number. He's had it since he ran in 2016, and he's never hesitated to use it when he's needed financial help for his campaigns... so, if he's lost it, I know he knows plenty of people who give it to him."Christie's pushback comes as calls from Sununu and others grow for him to drop out of the race, and throw his support behind Haley, has seen an upsurge in support in New Hampshire, according to recent polling.During a town hall in Rochester on Tuesday, Christie made it clear that he has no intention of supporting Haley unless she unequivocally declares that she will not be Trump's running mate if asked."I made that mistake. Eight years ago, I made an endorsement decision based on politics. Eight years ago when I supported Trump, not gonna make the same mistake again. Can't do it," he told the crowd.Although a voter asked him whether he believes in staying in the race, he is ultimately helping Trump become re-elected, Christie said that he still believes anything could change in the next two weeks before the primary, insisting that he will stay in the race as long as he sees a path forward."If there came a moment in time where I felt like I had no path to winning. I said this since June, I would get out -- that has nothing to do with Nikki Haley or anybody else in the race. That's about me and my supporters and the people that I owe my honesty and my integrity to," Christie said.WMUR reached out to Gov. Sununu's office, but we have yet to hear back.