"My job as chef diplomat is to ensure that the North Koreans know, we keep our channels open," Tillerson told the CBS news show "60 Minutes."

"I am listening. I am not sending a lot of messages back because there's nothing to say to them at this point. So I am listening for you to tell me you are ready to talk," he said, according to excerpts of the interview.

An Olympic-driven thaw in relations between Kim Jong Un's nuclear armed North Korean regime and South Korea has raised speculation that direct talks between Washington and Pyongyang could be on the horizon after months of sharp tension and heated rhetoric.

"They will tell me," Tillerson told "60 Minutes."

"We receive messages from them, and I think it will be very explicit as to how we want to have that first conversation."

The top US diplomat however stressed that no incentive was being offered to get Pyongyang to the table.

"We are not using a carrot to convince them to talk, we are using large sticks -- and that is what they need to understand," he said.

"This pressure campaign is having its bite on North Korea."

The North is subject to a series of UN Security Council sanctions over its banned nuclear and ballistic missile programs.

The United States has previously indicated Washington is open to direct talks, but Tillerson stressed earlier this month that the ball was now in Pyongyang's camp.

"We've said for some time it's really up to the North Koreans to decide when they're ready to engage with us in a sincere way, a meaningful way," Tillerson said on February 12, while on a stop in Cairo.

"They know what has to be on the table for conversations."

Washington says Pyongyang must take concrete steps towards denuclearization before talks can begin, while South Korean President Moon Jae-in has argued for closer involvement to engage the North in talks.

Moon last week received an invitation from Kim Jong Un for a summit in Pyongyang. The invitation was extended by the North Korean leader's younger sister Kim Yo Jong, who was part of a high-level delegation attending the Winter Games in the South.

When asked Saturday about a possible summit, Moon said that, despite the high hopes that have been raised, "I think it is a bit rushed."