Russian President Vladimir Putin have discussed the crisis over North Korea's nuclear programme with US President Donald Trump in a phone call, the Kremlin said.

The two leaders discussed "the situation in several crisis zones, with a focus on solving the nuclear issue on the Korean peninsula", it said in a statement, without elaborating.

Earlier this week, Washington said that it was ready to talk to North Korea, which has launched several intercontinental ballistic missiles in recent months, "without preconditions."

US Secretary of State Rex Tillerson said that while the Trump administration was determined to force Pyongyang to abandon its nuclear arsenal, it was willing to "have the first meeting without preconditions."

Mr Putin, in his annual press conference with hundreds of journalists in Moscow, welcomed the United States' "awareness of reality" in the crisis.

However, he called on all sides to "stop aggravating the situation" and said Moscow did not recognise North Korea's status as a nuclear power.