In an unexpected decision that blindsided his own senior officials and signaled a concession to Turkey, U.S. President Donald Trump on Wednesday suggested he is preparing to pull all U.S. troops out of Syria, a move that experts said will seriously undermine America’s already weak hand in the war-torn nation.

For Trump, it was the latest instance of conducting policy by tweet without forewarning, and it came even as key officials such as Syria special envoy James Jeffrey were signaling that U.S. policy was to stay in the country. Only the day before, State Department Deputy Spokesperson Robert Palladino told reporters that U.S. forces were there “to ensure the enduring defeat of [the Islamic State]. We’ve made significant progress recently in the campaign, but the job is not yet done.”

But on Wednesday morning, the president tweeted: “We have defeated ISIS, in Syria, my only reason for being there during the Trump presidency.” The tweet appeared to confirm multiple news reports that the administration is preparing for a “full” and “rapid” withdrawal of the 2,000 or so U.S. troops on the ground there.

Just hours later, reports emerged that all U.S. State Department officials are being evacuated from Syria within 24 hours. A State Department spokesperson told Foreign Policy that for “operational security reasons” she could not comment on “the movement of State Department personnel.”

Analysts said the abrupt turnabout exposed serious divisions within the administration about Syria—especially between Trump and two of his senior officials, National Security Advisor John Bolton and Secretary of State Mike Pompeo—and revealed just how weak a hand the United States is playing in a nation that Bashar al-Assad, with the assistance of Russian President Vladimir Putin, is gradually regaining control over. Just last week Brett McGurk, the presidential envoy for the global anti-Islamic State coalition, told reporters “it’s fair to say Americans will remain on the ground after the physical defeat of the caliphate.”

“Trump never really bought into the arguments by Bolton and Pompeo that Washington needed to maintain a military presence,” not only to deal with the Islamic State but also to counter Iran, said Joshua Landis, a Syria expert at the University of Oklahoma. “They walked him back once before, but he was clearly not convinced.”

The move would also present a prime opportunity for other actors in the region, such as Russia, Iran, and even the Islamic State itself, to take power, experts said.

“If Trump quits now, there are four winners: ISIS, Assad, Russia, and Iran,” writes Gayle Tzemach Lemmon of the Council on Foreign Relations in Defense One.

While the move signals tension between Trump and the Bolton-Pompeo camp, it may also indicate that Defense Secretary James Mattis is increasingly asserting his influence over the president. Mattis has long maintained that the United States is in Syria for one purpose: to ensure the lasting defeat of the Islamic State.

The Defense Department would not confirm the withdrawal or give a timeline for bringing troops home. Ahead of a meeting with Vice President Mike Pence at the Pentagon on Wednesday after the announcement, neither Mattis nor Pence would answer media questions about the withdrawal.

Dana White, the Pentagon’s chief spokesperson, stressed that while the coalition has liberated Islamic State-held territory, the campaign is not over.