Russia-backed Syrian forces step in as US retreats

Russia-backed Syrian forces wasted no time in taking advantage of an abrupt U.S. retreat from Syria on Monday, deploying deep inside Kurdish-held territory south of the Turkish frontier less than 24 hours after Washington announced a full withdrawal.

Washington's Kurdish former allies said they invited in the government troops as an "emergency measure" to help fend off an assault by Turkey, launched last week with "a green light" from President Donald Trump that the Kurds describe as a betrayal.

The Syrian government's deployment on Monday is a major victory for President Bashar al-Assad and his principal ally Russia, who gained a military foothold across the biggest swathe of the country that had been beyond their grasp. Under their deal with the Kurds, government forces are poised to move into border areas from the town of Manbij in the west to Derik, 400 km (250 miles) to the east.

Syrian state media reported that troops had already entered Tel Tamer, a town on the strategically important M4 highway that runs east-west around 30 km south of the frontier with Turkey.

State TV later showed residents welcoming Syrian forces into the town of Ain Issa, which lies on another part of the highway, hundreds of km (miles) away. An SDF media official said he could not confirm these deployments.

Ain Issa commands the northern approaches to Raqqa, former capital of the Islamic State "caliphate", which Kurdish fighters recaptured from the militants two years ago in one of the biggest victories of a U.S.-led campaign.

Much of the M4 lies on the southern edge of territory where Turkey aims to set up a "safe zone" inside Syria. Turkey said it had seized part of the highway. An official of the Kurdish-led Syrian Democratic Forces (SDF) said clashes were ongoing.

The swift Syrian government deployments came as the strategy the United States has pursued in Syria for the past five years crumbled overnight.