WASHINGTON -- CIA Director John Ratcliffe made an unannounced visit to Moscow on August 25, US officials confirmed to RFE/RL, a rare trip that comes as Washington's efforts to end Russia's war against Ukraine have stalled and tensions over Moscow's relationship with Iran have intensified.The reason for Ratcliffe's visit, the first publicly known trip he has made to Russia since becoming CIA director under President Donald Trump, was not immediately clear. US officials familiar with his travel confirmed he flew to Moscow but declined to disclose the substance of his meetings or say whom he met.The CIA and White House did not immediately comment publicly.First reported by CBS News, the visit was signaled by flight-tracking data showing a US military transport aircraft traveling from the United States through Latvia to Moscow. The plane, which appeared to have originated at Joint Base Andrews in Maryland, landed at Moscow's Vnukovo Airport early on August 25 and departed Russia later the same day, according to flight-tracking data.The unusual movement raised questions about why the head of the US intelligence agency would make a rare in-person trip to Russia at such a delicate moment. The most recent known visit to Moscow by a CIA chief was by Ratcliffe's predecessor William Burns, who met with Russian President Vladimir Putin in November 2021, three months before Putin launched the full-scale invasion of Ukraine.