Abu Bakr al-Baghdadi, the leader of Islamic State (IS) was wounded in an air strike and is no longer in command of the group, sources told the Guardian.
An Iraq-based source said Baghdadi was injured in a US-led coalition air strike in March.
At first it was thought he would not survive his injuries, but he has made a slow recovery, though not yet resumed responsibility for running the group's operations.
The Guardian's source said that since he was wounded an increasing number of decisions have been made by Shura councils and other senior members of the IS hierarchy.
There have been two prior claims that Baghdadi was killed, but both proved to be false. In this instance, an additional two sources have confirmed the air strike took place on 18 March.
Hisham al-Hashimi, an advisor to the Iraqi government said: "Yes, he was wounded in al-Baaj near the village of Umm al-Rous on 18 March with a group that was with him."
Al-Baaj, a district of Nineveh, is situated 200 miles west of Mosul, where much of Islamic State's activity has concentrated. Baghdadi is believed to have used this area as his base for its remote location, some distance from US activity.
The attack was targeting a convoy cars with regional IS leaders, it was not known if Baghdadi was with them.
Baghdadi declared himself the leader of IS when they split from Al-Qaeda. He then established himself the leader of the 'caliphate' the militant group has imposed in parts of Iraq and Syria in the past year.
Since 2011 the US government has had $10 million price tag on his head – less than half the amount offered for the al-Qaeda leader Ayman al-Zawahiri.
Two other Islamic State's key leaders were killed by air strikes in December.