US Secretary of State Mike Pompeo said on Wednesday he was dispatching a team to make preparations for the next summit between President Donald Trump and North Korean leader Kim Jong Un to be held somewhere in Asia late in February.

In an interview with Fox News Channel, Pompeo said the North Koreans had agreed the second summit between the two leaders would be held at the end of February.

"We'll do it someplace in Asia," he said.

"I am dispatching a team there. They're headed that way now to lay the foundations for what I hope will be a substantial additional step towards the path for not only denuclearization of the peninsula but a brighter future for the North Korean people," Pompeo said.

Pompeo did not name the summit venue. Vietnam said last week it had not been informed about any time or venue for a possible Trump-Kim summit, but that it was confident in its ability to host such a meeting.

Officials and diplomats said two weeks ago that Vietnam was keen to host the summit and two sources told Reuters that Hanoi was preparing to receive Kim on a state visit.

Singapore, where Trump and Kim met in June, and Bangkok have also been talked about as possibilities for the planned summit.

Last June's summit - the first between a sitting US president and a North Korean leader - produced a vague commitment by Kim to work toward the denuclearization of the Korean Peninsula, but he has yet to take what Washington sees as concrete steps in that direction.