'Americans should leave'

Syrian President Bashar al-Assad has warned US-backed Kurdish forces he would not hesitate to use force to retake the third of the country they control.

"The only problem left in Syria is the SDF," Assad told Russia Today in an interview aired yesterday, referring to the Kurdish-led Syrian Democratic Forces which has spearheaded battles against Islamic State group (IS) jihadists.

"We're going to deal with it by two options," he said.

"The first one: we started now opening doors for negotiations. Because the majority of them are Syrians, supposedly they like their country, they don't like to be puppets to any foreigners," Assad said in English.

"We have one option, to live with each other as Syrians. If not, we're going to resort... to liberating those areas by force."

The Kurds in oil-rich northeastern Syria have long pushed for increased autonomy in their heartland but Damascus has insisted it intends to reassert its authority over the entire country.

The SDF, dominated by the militia of a self-proclaimed Kurdish autonomous administration, has air support from the US-led coalition against IS and operates on the ground with US and French special forces.

"It's our land, it's our right and it's our duty to liberate it," Assad said. "The Americans should leave. Somehow they're going to leave."

An SDF spokesman told AFP the group's military command was aware of the interview but had no immediate comment.

Colonel Sean Ryan, spokesman for the US-led coalition, declined to specify how the body would react if government forces attacked the SDF.

"The SDF has done an amazing job helping get Daesh off the battlefield and they should be commended, not threatened," he told AFP yesterday.

Both the SDF and Russian-backed Syrian troops are engaged in separate operations against IS in east Syria, creating a highly volatile situation, where de-confliction mechanisms have already been tested several times.