Story highlights "Look, you always have to be concerned," Trump told CNN affiliate WTMJ in Wisconsin.

Trump said past presidents had put off dealing with North Korea.

(CNN) President Donald Trump said Tuesday 'you always have to be concerned' when he was asked how worried Americans should be about the possibility of nuclear war with North Korea.

"Look, you always have to be concerned," Trump told CNN affiliate WTMJ in Wisconsin. "You don't know exactly who you're dealing with. I had a great great meeting with the president of China and that meeting tells me a lot and you've seen a lot of things happen. They have a pretty good power, not a great power perhaps, but a pretty good power over North Korea. We're gonna see what happens. It's a very, very tricky situation."

North Korea's UN ambassador on Monday said US actions had "created a dangerous situation in which thermonuclear war may break out at any moment on the peninsula and poses a serious threat to world peace and security."

In his interview on Tuesday, Trump said past presidents had put off dealing with North Korea.

"Now I'm put in a position where he actually has nuclear and we're gonna have to do something about it," Trump said. "Hopefully he wants peace and we want peace and that's going to be the end determination, but we're going to see what happens."