CAIRO/BEIRUT - The Syrian Observatory for Human Rights told Reuters on Tuesday that it had "confirmed information" that Islamic State leader Abu Bakr al-Baghdadi has been killed.
The report came just days after the Iraqi army recaptured the last sectors of the northern Iraqi city of Mosul, which Baghdadi's forces overran almost exactly three years ago.
Russia's Defence Ministry said in June that it might have killed Baghdadi when one of its air strikes hit a gathering of Islamic State commanders on the outskirts of the Syrian city of Raqqa.
But Washington said it could not corroborate the death and Western and Iraqi officials have been sceptical.
Reuters could not independently verify Baghdadi's death.
"(We have) confirmed information from leaders, including one of the first rank who is Syrian, in the Islamic State in the eastern countryside of Deir al-Zor," said Rami Abdulrahman, the director of the British-based war monitoring group.
In Iraq, US Army Colonel Ryan Dillon, spokesman for the US-led coalition fighting Islamic State, said he could not confirm the news.
Abdulrahman said activists working with him in Deir al-Zor had been told by the Islamic State sources that Baghdadi had died, but not when or how.
The sources said Baghdadi had been present in the eastern countryside of Syria's Deir al-Zor province in the past three months.