DAMASCUS, April 12 (Xinhua) -- Russian military police have started deploying in Douma district in east of Syrian capital Damascus, after the Islam Army rebels handed over their medium and heavy weapons, a monitor group reported Thursday.

This came as the third batch of Islam Army rebels and their families left Douma toward the rebel-held city of Jarablus in northern Syria after midnight Thursday, according to the Syrian Observatory for Human Rights (SOHR).

In Moscow, Russian Defence Ministry also confirmed Thursday that its military police had started patrolling Douma to maintain law and order there.

The Russian military police are expected to be deployed in all of Douma in accordance with the deal reached on April 8, under which the Syrian official flag will be raised in Douma, the last rebel bastion in Eastern Ghouta.

The SOHR, which relies on a network of activists on the ground, reported that the leaders of Islam Army left in the batch after midnight Thursday.

It added that other Islam Army rebels, who remained in Douma, asked for the Russian military police to enter due to the lawlessness that has prevailed in Douma.

Douma has grabbed headlines worldwide recently as the Western governments and media accused the Syrian army of using chlorine gas on people there, sparking the U.S.-led West's threat of military strikes on Syria.

The Syrian government and Russia have denied the use of chemical weapons by Syrian army, accusing the rebels and the West of fabricating it to use it as an excuse to attack Syria.