"Today, militants detonated a tunnel under the western gate of the citadel, which is included in the UNESCO World Heritage List. The explosion has damaged the western part of the fortress," the source said.
Following the explosion, the militants attacked the Syrian army positions near the citadel, but the government forces repelled the assault, according to the source.
As a result of the clashes, one soldier was killed and three were injured.
The Citadel of Aleppo is a large medieval fortified palace in the center of the city, part of the UNESCO World Heritage Site. It is considered to be one of the oldest and largest castles in the world. The Syrian Army uses the Citadel as a military base.
The Aleppo Citadel has suffered a significant damage in the ongoing civil war, as during the 2012 Battle of Aleppo the fortress was damaged in clashes between the Syrian opposition and the government forces.
