The United States is prepared to engage with North Korea if Pyongyang demonstrates its denuclearization commitment, the White House said Wednesday, after Republican presidential candidate Donald Trump expressed his willingness to speak to North Korean leader Kim Jong-un.

"The United States has worked effectively with the international community, including countries like Russia and China, to isolate North Korea because of their failure to abide by their international obligations when it comes to their nuclear program," White House press secretary Josh Earnest said.

"Pressure can be relieved, and the international community is prepared to engage with North Korea as soon as they make clear their commitment to denuclearizing the Korean Peninsula and ending the kind of provocative rhetoric and acts that are so destabilizing to the broader region," he said.

But it's the North that has declined to pursue the path out of isolation, he said.

Earnest also said that the U.S. has succeeded in ramping up pressure on Pyongyang and even though the pressure has not yet had the desired effect, "there's ample evidence to indicate that they are feeling that pressure."

On Wednesday, Trump said in an interview with Reuters that he's willing to hold talks with the North's leader.

"I would speak to him, I would have no problem speaking to him," Trump was quoted as telling Reuters.

Trump also reiterated that he would pressure China to rein in the North, according to the report.

It was the first time Trump has expressed a willingness to talk to the North's leader.

Trump has expressed deeply negative views of Kim, calling him a "madman" and a "maniac."

Six-party nuclear talks with North Korea have been stalled since late 2008. The North demands the unconditional resumption of negotiations, while the U.S. says that Pyongyang must first take concrete steps demonstrating its denuclearization commitments. (Yonhap)