"Something very big has just happened!" the president said on Twitter late Saturday.
President Donald Trump will make a statement at 9 a.m. Sunday, the White House said.
It did not provide additional details, but the statement will come after sources told NBC News that Islamic State group leader Abu Bakr al-Baghdadi was the target of a deadly U.S.-led raid in northwestern Syria.
Trump hinted at the news late Saturday.
"Something very big has just happened!" he said on Twitter.