Syrian embattled president Bashar al-Assad has claimed that his government is kept informed about the US-led coalition's air strikes against the Islamic State (Isis) by third parties including Iraq.

In an interview with the BBC, Assad said there was no direct co-operation with the Obama administration, whose air force has been conducting raids on IS positions in Syria since September.

But he admitted a sort of indirect cooperation, if irregular, was taking place.

"That's true, through third parties, more than one party, Iraq and other countries, sometimes they convey message(s), general message(s), but there is nothing tactical," Assad said.

"There is no dialogue. There is, let's say, information, but not dialogue."

Arab states which are part of the US coalition against IS have denied cooperating with Assad, who they have urged to resign since the start of the uprising against his rule in 2011.

But since IS seized large swaths of land across Syria and Iraq, officials have started considering working with the Syrian leader to fight against a common enemy.

However, the Syrian president has ruled out joining the international coalition against the Islamist militant group.

"No, definitely we cannot and we don't have the will and we don't want, for one simple reason - because we cannot be in an alliance with countries which support terrorism," he said.

The Assad government routinely refers to the internal opposition, supported by Gulf states such as Saudi Arabia and Qatar, as "terrorists".