Takfiri militants operating against the government of Syrian President Bashar al-Assad are using their captives as “human shields,” a monitoring group says.

The so-called Syrian Observatory for Human Rights said on Sunday that terrorist group calling itself Jaish al-Islam has put captive Syrian soldiers and civilians in metal jails on the outskirts of the capital, Damascus.

Rami Abdel Rahman, the head of the Britain-based rights group, said that the terrorist group places these cages in public squares in the Eastern Ghouta region in an attempt to "prevent…bombardment" by Syrian forces.

“Jaish al-Islam is using these captives and kidnapped people - including whole families - as human shields,” he said.

The terrorists reportedly keep five men and women in each cage.

Militants from terrorist group calling itself Jaish al-Islam hold a position behind a sand barrier on August 25, 2015 on the frontline in the Bashkoy area, on the northern outskirts of Aleppo. (AFP photo)

Rahman further noted that most of the civilians were kidnapped by the terrorist group two years ago outside Adra al-Ummaliyah, a neighborhood in Eastern Ghouta.

Militants operating in the region regularly fire rockets at the capital, causing casualties and material damage.

A Syrian police source said that a Syrian girl was killed in a mortar attack carried out by the so-called Jaish al-Islam group landed on the residential neighborhood of Qusour in the capital. Another civilian was injured in the attack.

Syrian people walk amid the rubble of destroyed buildings in the militant-held area of Douma, east of the capital, Damascus, October 29, 2015. (AFP photo)

The mortar attack came as the Syrian army successfully carried out operations to liberate several villages and towns, including Maraen, Hamimeyeh, Hamidah, Hamidi, Meshrfeh and Sabhiyeh on the southwestern outskirt of Aleppo city, northwestern Syria.

The conflict in Syria has taken toll on the lives of over 250,000 since March 2011, according to the UN. More than 12 million people, including over 5.6 million children, also remain in need of humanitarian assistance.

The foreign-sponsored militancy has displaced 7.6 million Syrians.