U.S. Defense Secretary Jim Mattis says he believes that the leader of the extremist Islamic State (IS) group, Abu Bakr al-Baghdadi, is still alive.
His comments on July 21 come weeks after Russia and the Britain-based Syrian Observatory for Human Rights had said Baghdadi had been killed in a Russian air strike, although U.S., Iraqi, and other Western officials have never confirmed the report.
"I think that he's alive, and I'll believe otherwise when we know we've killed him. But we're going after him… we assume he's alive,” Mattis told reporters at the Pentagon.
Nicholas Rasmussen, the director of the U.S. Counter-Terrorism Center, echoed those comments.
He said he has “seen nothing that would lead me to believe” that Baghdadi “has been removed from the battlefield."
"We know a good bit,” he added. “We just don’t have information that would confirm his death."
Baghdadi's death has been erroneously announced several times in the past.
From the Iraqi city of Mosul in July 2014, Baghdadi declared an Islamic "caliphate" over territory held by IS fighters in Iraq and Syria.
However, U.S.-led Iraqi troops have retaken Mosul, and coalition forces have pushed back IS in the rest of Iraq and in Syria.