The phone call came on the same day that the president signaled a willingness to talk to North Korean leader Kim Jong Un.

"Sure, I always believe in talking," Trump said Saturday, later saying, "absolutely I would do that, no problem with that at all."

He added that he would like to see North Korea participate in the upcoming Winter Olympics in South Korea.

"I'd like to see them getting involved in the Olympics and maybe things go from there. So I'm behind that 100 percent," the president told reporters at Camp David, ahead of reported talks this week between South Korea and North Korea.

Trump had previously insisted that he would not take part in any talks with Pyongyang unless Kim agreed to stop its pursuit of nuclear weapons, after a series of missile and nuclear weapons tests escalated tensions between the U.S. and North Korea.

The two world leaders also found common ground over the protests erupting across Iran, with scores of people demonstrating against the country's clerical leadership and the state of the economy.