Russia said Friday it had launched "humanitarian operations" in Syria where it is carrying out a bombing campaign against the Islamic State group, claiming peaceful life was slowly returning to the war-torn country.

"The inhabitants are gradually coming back to Syrian cities and peaceful life is returning," General Sergei Rudskoi, a senior Russian General Staff official, told reporters.

"In this context, the implementation of humanitarian operations will be a new line of work for the Russian armed forces in Syria," he said in televised comments.

"Currently most of the aid is being sent to the city of Deir Ezzor which has been besieged by ISIL terrorists for a long time," Rudskoi said, using another term for IS.

He said Syria's Il-76 military transport planes had airdropped 22 tonnes of humanitarian aid to Deir Ezzor using Russian equipment.

"It will be distributed by local authorities," Rudskoi added.

"Our work in this direction will continue," he said.

"In the future we will give to the Syrian people all possible assistance when it comes to liberating the country from extremists and rebuilding peaceful life."

Russia has decided to launch its own humanitarian operations in Syria because most of the aid has so far gone to rebel-controlled areas, often ending up in the hands of "extremists," Rudskoi said.

"Attempts have repeatedly been seen to supply arms and ammunition and evacuate wounded fighters under cover of humanitarian convoys," he added.

Moscow launched a bombing campaign against IS and other "terrorists" on September 30, saying it needed to target jihadists before they crossed into Russia.

The West has criticised Russia's foray into the multi-front conflict, accusing Moscow of targeting not only the IS group but also moderate rebels fighting the regime.

In August, Russia and Syria signed an agreement giving Moscow the right to retain an open-ended military presence in the war-torn country, Moscow revealed on Thursday.