Watch: Insurgents shoot down Syrian helicopter amid offensive

The shooting down of the helicopter, which killed its two crew members, came as government forces came closer to capturing the last rebel-held part of a strategic highway linking southern and northern Syria, which would bring the road under the full control of Syrian President Bashar Assad for the first time since 2012.

Beirut:Syrian rebels shot down a government helicopter Tuesday in the country's northwest where Syrian troops are on the offensive in the last rebel stronghold, opposition activists said.

The shooting down of the helicopter, which killed its two crew members, came as government forces came closer to capturing the last rebel-held part of a strategic highway linking southern and northern Syria, which would bring the road under the full control of Syrian President Bashar Assad for the first time since 2012.

With backing from Russia, Syrian troops have been on the offensive for weeks in the last rebel stronghold in Idlib province and parts of nearby Aleppo, triggering a humanitarian crisis with some 700,000 people fleeing their homes. Hundreds of civilians have also been killed, according to the United Nations.

The fighting recently escalated with two separate clashes between Syrian and Turkish troops killing 13 on each side.

Turkey, which is a main backer of the Syrian opposition, has sent hundreds of vehicles into Idlib apparently to prevent government forces from reaching the border areas with Turkey. Turkey is home to some 3.6 million Syrian refugees and has concerns of more flowing into its border.

Rebel fighters look at a Syrian government helicopter that was shot down in Idlib province, Syria

The fighting on Tuesday concentrated near the village of Nairab as rebels, with the backing of Turkish artillery, tried to retake the village that they lost last week, according to opposition activists.

Amid the fighting near Nairab, insurgents shot down the government helicopter gunship, killing the two crew members onboard, according to the Britain-based Syrian Observatory for Human Rights and Step news agency, an activist collective.

The Observatory also reported that Syrian troops have secured the highway that links southern Syria with the northern city of Aleppo.

Syrian government helicopter bursts in flames after it was shot by a missile in Idlib province

An unnamed Syrian military official was quoted by pro-government media as saying that they still have five villages to take before securing the highway.

The highway, known as M5, starts in the country's south near the border with Jordan and moves north all the way to Aleppo. Its capture is vital for the country's economy as well as for sending reinforcements.

The highway's capture will mark another victory for Assad whose forces have been making solid gains since the end of 2015 with the help of Russian airstrikes and Iran-backed fighters on the ground.

For the past three years, government forces have been capturing parts of the 450-kilometer (280-mile) highway that cuts through the country's four largest cities.