An explosion has hit the area of Damascus International Airport and Mezze military air base followed by a fire in the same place, activists said.

The blast, reported by several activists’ networks, occurred near the Damascus airport road early on Thursday.

The cause of the explosion was still not clear.

Rami Abdurrahman, head of the UK-based Syrian Observatory for Human Rights, said the blast was heard across the capital, jolting residents awake. 

Activist-operated Dairy of a Mortar, which reports from Damascus, said the explosion near the airport road was followed by flames rising above the area.

A pro-government site Damascus Now said the blast was near the city’s Seventh Bridge, which leads to the airport road.