WASHINGTON (Reuters) - CNN said on Thursday that North Korea would imminently release three Americans held as prisoners, as expectations grew that Pyongyang would make the gesture ahead of an unprecedented U.S.-North Korea summit due to take place in coming weeks.

CNN, citing an unnamed source, said the groundwork for the move came two months ago when North Korea's foreign minister traveled to Sweden and proposed the idea.

Rudy Giuliani, who joined President Donald Trump's legal team last month, told Fox News Channel that North Korea would release the three prisoners on Thursday. It was not immediately clear whether Giuliani, a former mayor of New York City, had direct knowledge of negotiations around the issue.

Trump administration officials have pressed for the Americans' release as a show of goodwill by North Korea before the meeting between Trump and North Korean leader Kim Jong Un, which is expected to take place in late May or early June.

White House spokeswoman Sarah Sanders said she could not confirm details about the release, but she said Washington was "cautiously optimistic" about its ongoing talks with Pyongyang.

"Certainly, that would be an incredible step and certainly a sign of goodwill moving into the summit, moving into these discussions with North Korea. I can't comment any further at this point," Sanders said in an interview with Fox News.

Asked about Giuliani's comment, a State Department official reiterated on Thursday that the department could not confirm whether the Americans were being released and was working to see them come home as soon as possible.

In a Twitter post late on Wednesday, Trump said, "As everybody is aware, the past Administration has long been asking for three hostages to be released from a North Korean Labor camp, but to no avail. Stay tuned!"

On Wednesday, South Korean media reports quoted a South Korean activist who said North Korea had moved the three Americans from a labor camp to a hotel on the outskirts of Pyongyang.

A U.S. official said on Wednesday the U.S. government was looking into the reports. Speaking on condition of anonymity on Wednesday, the official said there was no immediate confirmation of any change in the detainees' status.

Even as Washington presses for the release of the three, the parents of a U.S. college student who died last year soon after being release from captivity in North Korea have sued Pyongyang over their son's death, saying Otto Warmbier was "brutally tortured and murdered."

Details of the location and date of the planned Trump-Kim meeting have not yet been announced, although Trump said on Tuesday that they may be announced soon.





(Reporting by Makini Brice in Washington; Additional reporting by Christine Kim in Seoul; Editing by Frances Kerry)