The Trump administration says it has started working on details for a historic meeting between Donald Trump and DPRK leader Kim Jong Un. But Washington says Pyongyang will need to demonstrate it has taken certain steps by then. CGTN's Roee Ruttenberg has more from Washington.  

The White House on Friday defended its surprise decision to accept an offer to have U.S. President Donald Trump meet his DPRK counterpart Kim Jong Un. That invitation delivered just 24 hours earlier by a visiting South Korean delegation suggesting the two may sit face-to-face within months.

SARAH SANDERS WHITE HOUSE PRESS SECRETARY "A time and place have not yet been determined. We'll certainly make those announcements when more decisions and more information is available on that front."

The White House took credit for the offer-saying the U.S. president's so-called maximum pressure campaign against Pyongyang made the difference.

SARAH SANDERS WHITE HOUSE PRESS SECRETARY "We're not going to step back or make any changes to that. We're going to continue in that effort and we're not going to have this meeting take place until we see concrete actions that match the words and the rhetoric of North Korea."

According to administration, officials that includes a promise by Pyongyang to freeze its nuclear weapons program, to halt all missile tests, and to take steps toward denuclearization. But critics warn: promises are just words, on both sides.

MAZIE HIRONO US DEMOCRATIC SENATOR "I hope that we do not have what I would characterize as the 'Tuesday Trump', who goes in and has these one-on-one talks with Kim Jong Un, promises all kinds of things, and then on Thursday, he walks back. We need to have a full-of-government preparation."

The Americans insist they made no concessions to the DPRK. And U.S. Secretary of State Rex Tillerson said the meeting would be talks, not a negotiation.

REX TILLERSON US SECRETARY OF STATE "President Trump has said for some time that he'd be open to talks and he'd willingly meet with Kim Jong Un when conditions were right and the time was right."

Tillerson's State Department is short on top diplomats on the Korean Peninsula. The US's DPRK envoy recently retired-reportedly frustrated by the president. And the U.S. still doesn't have an ambassador to South Korea. Trump has yet to appoint one.

ROEE RUTTENBERG WASHINGTON "No sitting U.S. President has ever met face-to-face with a DPRK leader. Jimmy Carter and Bill Clinton did so, separately, after they left office. IF this meeting happens, WHEN this meeting happens, and WHERE this meeting happens will all be crucial. One analyst compares it to a game of poker: each side may win it all, or lose it all. Roee Ruttenberg, CGTN, in Washington."