BEIRUT -- U.S.-backed Syrian fighters fought Islamic State militants in the heart of Raqqa, the extremists' self-styled capital, on Monday, as scores of civilians fled areas controlled by the group.
The Kurdish-led group has been one of the most effective forces fighting IS in Syria, but has also clashed with Turkish-backed Syrian forces elsewhere in the country. As it battled ISIS in Raqqa, the SDF also fought Turkish-allied Syrian forces in Ein Daqna, in the neighboring Aleppo province, according to Syrian activists and Turkish media.
The Syrian Democratic Forces, aided by the U.S.-led coalition, launched their offensive to capture Raqqa on June 6, and have since taken several areas. The Britain-based Syrian Observatory for Human Rights said Monday's fighting is concentrated in Raqqa's southwestern neighborhood of Yarmouk as well as a central area close to the Old City.
The SDF says intense fighting is underway in central Raqqa, adding that its fighters have taken positions near a centuries-old mosque known as the Old Mosque. The Kurdish-run Hawar news agency says some 180 civilians were able to flee areas controlled by ISIS, while the Observatory put the number in the hundreds.
The SDF said 11 ISIS fighters have been killed in the clashes since Sunday. The ISIS-linked Aamaq news agency said 14 SDF fighters were killed in the fighting in Raqqa on Sunday alone.
The intensification of fighting comes a week after Iraqi forces declared victory against ISIS in the northern Iraqi city of Mosul, the largest the extremists have held. The loss of Raqqa would deal a major blow to ISIS, but the group still holds wide areas of the eastern province of Deir el-Zour, bordering Iraq.
That province figures to be the backdrop to the next phase of the war on ISIS, with government forces backed by Russia and Iran approaching from the west and south. Pro-government forces reached the edges of the Bashari mountain range on Monday, after seizing the Zamla natural gas field one day earlier, the Observatory and Syrian military media reported. The advance secures further natural resources revenues for the government and puts government forces in a position to penetrate the Deir el-Zour countryside.
The SDF is dominated by a Kurdish militia known as the YPG, which Turkey views as an extension of the Kurdish insurgency raging in its own territory. Turkish troops and allied Syrian forces rolled into Syria last year in order to battle ISIS and halt the advance of the SDF. The U.S.-led coalition has sought to stop the fighting between Turkey and the SDF, both of which are allies against ISIS.
The website of Turkey's pro-government A Haber television said Turkish-backed Syrian opposition fighters launched a "large" operation against the SDF in Ein Daqna, close to the Turkish border. The website quotes unnamed local sources as saying that intense clashes are ongoing.
The Observatory said Monday's fighting killed two Turkey-backed fighters and left several SDF fighters wounded. A Haber said at least one Turkish-backed fighter was killed and some 14 were wounded.
Rezan Hiddo, an SDF political officer, said the group had repelled the assault on Ein Daqna. Hiddo said Turkish artillery struck the village as well as near a Russian military outpost in nearby Kafr Janneh, which is also under SDF control. Russia deployed what it called observer units into the region earlier this year to discourage clashes between Turkey and the SDF.
"We are waiting for the American government to apply diplomatic pressure on Turkey to halt the aggression," said Hiddo.