Turkish-backed Syrian rebels shot down a government helicopter west of Aleppo in Syria's northwestern Idlib region, where violence and displacement have spiked in recent weeks, Turkish and Syrian state media said on Friday.

A rebel military source and eyewitnesses told Reuters Russian jets had been targeting areas in the countryside west of Aleppo earlier on Friday, but they evacuated back to the city after the helicopter was downed.

"One of our military helicopters was hit by an enemy missile in the western countryside of Aleppo...where armed terrorist organizations supported by Turkey are deployed, and this led to the fall of the helicopter and death of its crew," Syrian state news agency SANA cited a military source as saying.

The helicopter was struck as it flew over the front lines after leaving Aleppo, which is controlled by the government, Turkish state-owned Anadolu news agency said. Rebels downed another government helicopter on Tuesday near the town of Nairab, to the south.

Syrian state-run al-Ikhbariya TV meanwhile broadcast what it said was its crew driving for the first time into Aleppo via the M5 international highway that has been a focal point of President Bashar al-Assad's latest military campaign.

Escalating tensions, Syrian advances updates

The downing of the helicopter came as tensions between rebel-backer Turkey and Russia-supported Syria have been rapidly escalating, with a series of tortuous hostilities between the two state armies culminating in direct mutual engagement on February 3.

Turkey's military has reportedly sent additional arms and troops to Idlib, on its southern border, to confront a push by Russia-backed Syrian government forces to retake the country's last major rebel stronghold after nearly nine years of war.

The Syrian Observatory war monitor said on Friday that Turkey had deployed around 6,500 soldiers to reinforce existing units in northwest Syria, as well as some 1,900 military vehicles since early February.

Read more: Turkish tanks deployed to border with Syria amid fears of fresh refugee influx

Syrian government forces, in the meantime, have recently made two significant territorial gains, capturing the key strategic towns of Maaret al-Numan on January 29 and Saraqeb on February 8.

Maaret al-Numan lies on the key M5 highway connecting the capital Damascus to Aleppo

Saraqeb sits at the crossroads with the M4, the main east-west highway in Idlib which links Aleppo with the Mediterranean port city of Latakia, a government bastion. 

While Ikhbariya said the M5 was now fully under the control of Syria's army, the M4 is still largely controlled by jihadists and Turkey-backed rebel forces.

Freezing weather compounds crisis for displaced in Syria

As the military campaign in Idlib province and the nearby Aleppo countryside claimed the lives of hundreds of civilians, a bitter winter has compounded the pain of the displaced Syrians.

The freezing weather has contributed to at least 10 deaths, including four who suffered hypothermia, a family of four that died of suffocation in their tent and two who burned to death when their tent caught fire, according to Mohammed Hallaj, a coordinator for the area's Response Coordination Group.

The government's military assault on Idlib has uprooted more than 830,000 people since December 1, most of them fleeing toward safer areas near the border with Turkey, U.N. spokesman Stephane Dujarric said Friday. At least 143,000 people have been displaced in the last three days.

(With input from Reuters, AP)