A flurry of diplomacy - from Asia to Europe to the Americas. All ahead of a planned face-to-face meeting between US President Donald Trump and DPRK leader Kim Jong-un. The White House says President Trump still hopes that historic summit will happen before the end of May. Many details, still being work out behind closed doors. CGTN's Roee Ruttenberg has that story.

As the DPRK Foreign Minister Ri Yong Ho was in Stockholm for surprise closed-door talks with Swedish officials, South Korea's top diplomat was in Washington. Kang Kyung-wha's visit comes just days after US President Donald Trump accepted an offer to meet face-to-face with DPRK leader Kim Jong-un.

KANG KYUNG-WHA SOUTH KOREAN FOREIGN MINISTER "We're cautiously optimistic that the talks will happen and that this will be a breakthrough for a peaceful resolution of the North Korean nuclear issue."

Back in Seoul, officials said they were seeking high-level talks with Pyongyang this month-ahead of their own summit with Kim set for April.

IM JONG-SEOK CHIEF OF STAFF TO THE SOUTH KOREAN PRESIDENT "We've decided to narrow down the agenda topics to denuclearizing the Korean peninsula, securing permanent peace to ease military tension and new, bold ways to take inter-Korean relations forward."

South Korea says President Moon Jae-in hopes to meet with Trump before the US president's historic summit with the North's leader. According to the White House, Trump and Moon spoke by phone on Friday, and "agreed that concrete actions, not words, will be the key to achieving permanent denuclearization of the Korean Peninsula. Until then, Washington's approach to Pyongyang would remain unchanged".

SARAH SANDERS WHITE HOUSE PRESS SECRETARY "We are continuing our maximum pressure campaign on North Korea. We are continuing to ask our allies to engage in that maximum pressure campaign, not to let up that point for any reason until we see real progress on the promises made by the North Koreans."

The DPRK has yet to confirm the meeting. But Stockholm on Friday said Sweden may play a part.

MARGOT WALLSTROM SWEDISH FOREIGN MINISTER "We are hoping that if we can use our role and also our contacts then we will put it to the best use. And then it's for the parties to decide what is the way forward and the process from now on."

Washington's former envoy to the DPRK - who quit last month - said he understood the resistance of some in the White House towards Pyongyang.

JOSEPH YUN FORMER US ENVOY TO THE DPRK "They have been relentless in testing missiles, nuclear devices. So this is not easy. It's a complicated problem. But I know we're getting a great start if we start off with a summit."

He said the president has struggled to get his whole team on the same side.

ROEE RUTTENBERG WASHINGTON DC "That may help explain some of the rumblings we've heard in recent days. That Donald Trump himself made the decision to accept the offer. That his now-fired Secretary of State and he didn't gel. And that his National Security Adviser - who openly floated the idea of a pre-emptive strike -- may be on his way out. Roee Ruttenberg, CGTN, in Washington."