A Syrian military helicopter was shot down over the last major rebel bastion in northwest Syria on Friday, the second such incident in a week of high tensions with Turkey. The attack in a region where Turkish troops and Russian-backed government forces have engaged in multiple clashes came as Washington urged Ankara to look to its Western allies in light of Moscow's actions.

It came as Syrian and Russian forces pressed a deadly offensive against the shrinking pocket in the country's northwest, claiming the lives of nine civilians on Friday. "At approximately 13:40 (1140 GMT), one of our military helicopters was hit by a hostile missile in the western countryside of Aleppo," Syrian state news agency SANA said.

"This led the helicopter to crash, killing all crew on board." SANA said the aircraft was downed near the town of Urum al-Kubra, where Turkey-backed rebels operate, but did not say who was behind the attack. The Turkey-backed National Liberation Front rebel group claimed responsibility in a statement posted on the Telegram app.

The Syrian Observatory for Human Rights said two pilots were killed in the downing of the helicopter. An AFP correspondent saw the mangled remains of the chopper and the blood-stained fatigues of one of the pilots. Three days earlier another Syrian military helicopter was downed over Idlib province, killing at least three crew members. Turkish media blamed that attack on rebels but the Observatory said Ankara's troops had fired rockets at the aircraft over the village of Qaminas, southeast of Idlib city. Turkey did not claim responsibility.

Turkey tensions

Since December Syrian government forces have pressed a blistering assault on the last major rebel pocket in the northwestern Idlib region and parts of neighbouring Aleppo and Latakia provinces. Eight civilians including three children were killed in bombardment Friday, the Observatory said, adding that five died in Russian raids near the deserted city of Atareb. Government forces are within five kilometres (three miles) of the city, the monitor said.