Washington - US President Donald Trump's UN ambassador said on Sunday the administration isn't changing its conditions regarding talks with North Korea amid growing tensions over the North's nuclear and missile programmes.Nikki Haley made clear that North Korean leader Kim Jong Un would first need to stop weapons testing for a "significant amount of time".Trump had said on Saturday that he was open to talking to Kim. It appeared to be a softening of rhetoric, given that Trump lectured Secretary of State Rex Tillerson in 2017 that it would be a waste of time "trying to negotiate with Little Rocket Man", Trump's nickname for Kim.But Haley insisted that Trump was reiterating his past position in his comments from Camp David over the weekend."There is no turnaround," she said. "What he has basically said is 'yes, there could be a time where we talk to North Korea,' but a lot of things have to happen before that actually takes place. They have to stop testing. They have to be willing to talk about banning their nuclear weapons.""It's a dangerous situation," Haley added.Trump's comments came as the first formal talks between North and South in more than two years are set to take place in a border town on Tuesday; the rivals are trying to find ways to cooperate on the Winter Olympics that begin next month in the South. Tensions are high because of the North's nuclear and missile programmes.Haley said it was her understanding that the two sides were limiting their talks to the Olympics, "but you know, those two countries have to get along"."That's good for the United States that they can at least start getting back into talks," she said.'Drawing closer to war'The Trump administration has agreed to delay joint military exercises with South Korea until after the Olympics. Defence Secretary Jim Mattis insisted the move was a practical necessity to accommodate the Olympics and was not a political gesture.In recent weeks, Trump and Kim have traded barbs about their arsenals and the "nuclear button" on their desks, raising fears the two countries could be drawing closer to war.On Sunday, CIA Director Mike Pompeo stressed his view that an attack from North Korea was not imminent, though the North appeared to be a few months away from reaching the capability of putting a US city at risk of a nuclear attack. Pompeo defended Trump's tweets as appropriate and "consistent" with US goals of denuclearising the Korean peninsula."The president has made very clear that were going to do everything we can to do that in a way that doesn't involve military action", Pompeo said, "but has equally made clear that we're not going to stand for allowing Kim Jong Un to hold Los Angeles, or Denver, or New York at risk".Expressing skepticism that North Korea was sincere in trying to improve relations, Pompeo added: "We'll just have to wait and see how the conversations go [on] Tuesday."Haley spoke on ABC's "This Week" and Pompeo was on "Fox News Sunday" and CBS' "Face the Nation."