At least 40 rebels killed after their convoy comes under attack by unidentified jets in Hama, monitoring group says.

At least 40 fighters of the Islamic State of Iraq and the Levant (ISIL) have been killed in an air strike on their convoy in the Syrian province of Hama, a UK-based monitoring group has said.

The Britain-based Syrian Observatory for Human Rights said on Sunday that unidentified warplanes hit the 16-vehicle motorcade overnight on Sunday in Hama province.

The Observatory, which monitors the war in Syria and has a network of sources on the ground, was not immediately able to say whether the raids were carried out by Russian warplanes or Syrian regime ones.

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“But they don’t belong to the coalition led by Washington,” Observatory chief Rami Abdel Rahman told the AFP news agency.

Rahman said that the convoy was hit as it was heading from the self-declared ISIL capital of Raqqa in northern Syria to the Hama countryside.

Russia, a key ally of the Syrian regime of President Bashar al-Assad, has been carrying out a campaign of air strikes against his opponents since September 30.

Last year, a US-led coalition launched an air campaign against the group which controls swaths of Syria and neighbouring Iraq.