At a news conference during a visit to Nigeria’s capital, Abuja, Tillerson said that the U.S. expects to hear directly from Pyongyang.

He described plans for the possible meeting as being in the "very early stages and said many steps need to occur before any talks takes place but did not clarify what those steps would be.

South Korea's national security advisor Chung Eui-Yiong late week told reporters at the White House that Trump agreed to meet Kim by May after Kim "expressed his eagerness to meet President Trump as soon as possible".

Tillerson also said the location for the meeting has not been determined but it is "very important that those conservations are held quietly".

Trump and Kim have a year-long history of acrimonious rhetoric, with Trump notably threatening the North Korean leader, whom he has called "little rocket man", with "fire and fury", and Kim retorting "a frightened dog barks louder" after Trump addressed the UN.