A historian explains why U.S. sanctions and Iran and Russia’s entanglements in other wars helped create an opening for rebel groups to overrun the Syrian Army.

Turkey will be the key player in ending the rebel push by Syrian insurgents against President Bashar al-Assad.

Syria’s devastating civil war, responsible for more than 300,000 deaths, was never officially resolved. Lightning gains by rebels opposed to President Bashar al-Assad were opportunistic, but also indicated years of patient preparations.

Syria holds strategic importance for Moscow and Tehran, which have both bolstered Syrian President Bashar Assad's regime at critical moments.

Russia said on Wednesday that it strongly backs the actions of the Syrian leadership to counter an offensive by what it said were terrorist groups receiving support, including drones and training, from outside the country.

As Syrian and Russian jets continue pounding targets, two airstrikes hit a group of four hospitals and the health directorate building in Idlib city, according to the Syrian Civil Defense that operates in opposition-held areas,