Trump made the comments twice on Friday — first in a tweet proclaiming “The U.S. has secured the Oil,” and later while discussing the temporary cease-fire reached between Turkish and Kurdish fighters in northern Syria a day earlier.

“We’ve taken control of the oil in the Middle East — the oil that we’re talking about, the oil that everybody was worried about,” Trump said during a White House event to mark the first all-female space walk. “The U.S. has control of that.”

Trump ignored a shouted question about his oil remark, and the National Security Council declined to comment on the matter.

The comments puzzled energy analysts and Middle East experts in Washington. Nicholas Heras, a fellow at the Center for a New American Security, wondered in a tweet if the remark signaled the U.S. might keep a residual force in parts of Syria.

Oil fields in northeastern Syria had about 2.5 billion barrels of oil reserves as of 2018, according to BP Plc’s annual Statistical Review.

U.S. control might be news to OPEC — the producer group that meets periodically to boost or cut production to keep the oil market in balance — and has five members in the Middle East: Saudi Arabia, Kuwait, Iraq, Iran and the U.A.E.