Hayat Tahrir al-Sham, an organisation that includes former operatives from Al-Qaeda's Syria affiliate, sealed off the village of Barisha, near the Turkish border, following US media reports of the jihadist leader's killing.

According to the Syrian Observatory for Human Rights war monitor, US helicopters airlifted troops to the village for a nighttime raid that led to clashes.

At least nine people were killed in the operation, which lasted about two hours, but the Observatory could not confirm that Baghdadi was among them.

US President Donald Trump said he would soon make a major announcement and officials in Washington have told US media outlets that an operation did indeed target Baghdadi.

Excavators were at work near the flattened remains of the house that appeared to have been the main target of the airborne operation.

The area is nominally under the control of HTS, which administers much of the Idlib enclave, one of the last major parts of Syria outside the control of President Bashar al-Assad's regime.

Ankara has some sway over HTS but has failed to rein it in despite deals Turkey has stuck with Russia, Damascus's main backer and the most powerful foreign broker in Syria.

Al-Qaeda and IS have long been rivals.

According to the Observatory and local sources, IS fighters -- who have been operating underground since the group lost its last fixed positions in Syria earlier this year -- were also present in the area.

Another organisation with a presence in the area is Hurras al-Deen, a hardline jihadist group linked to Al-Qaeda that has smaller numbers but seasoned fighters.