Clashes between rebels and government security forces have reportedly forced the closure of the international airport in the Syrian city of Aleppo.

Rebel forces have been targeting the country’s airports in an attempt to halt the regimes use of aircraft in attacks against them. The opposition groups now largely control the biggest city in Syria.

According to the Syrian Observatory for Human Rights, clashes have also been taking place by the Aleppo office of the Airforce Intelligence and attacks on the civilian airport began on 31 December.

Syria’s bloody civil war has left 40,000 people dead so far.