DAMASCUS - Dozens of civilians left the besieged and battered opposition-held east of Syria's Aleppo city on Saturday through a "humanitarian corridor" to the government-held west, state media reported.

The Britain-based Syrian Observatory for Human Rights also reported that "a number" of civilians had crossed into government territory.

The crossings were the first major movement of people from the besieged districts of the city after regime ally Russia announced Thursday that passages would be opened for civilians and surrendering fighters.

State television broadcast footage showing civilians, mostly women and children, walking under the watch of government troops and boarding buses. "This morning dozens of families left via the corridors identified... to allow the exit of citizens besieged by terrorist groups in the eastern neighbourhoods," state news agency SANA reported. "They were welcomed by members of the army and taken by bus to temporary shelters," it added.

It said that "a number" of women over the age of 40 had left in addition to the families and were taken to shelters.

SANA added that "armed men from eastern neighbourhoods of Aleppo" turned themselves over to army soldiers in Salaheddin district, without specifying a number or giving further details. State television broadcast footage of a handful of men entering government territory carrying their weapons aloft, some with scarves wrapped around their faces. Once Syria's economic powerhouse, Aleppo has been ravaged by the war that began in March 2011 with anti-government protests. It has been roughly divided between government control in the west and rebel control in the east since mid-2012.

Eastern neighbourhoods have been under total siege since July 7, when government forces seized the only remaining supply route.

The encirclement has caused food shortages and spiralling prices in the east, and raised fears of a humanitarian crisis for the estimated 250,000 people still living there. But the humanitarian corridors announced by Russia have been met with suspicion by residents, as well as countries including the United States.

Many residents said they were afraid to leave via government-controlled routes into regime-held territory.

"I want to leave, but not to government-held areas," said Abu Mohamed, a 50-year-old father of four living in Al-Shaar district. "I'm very afraid that they will take my 17-year-old son and force him to sign up for military service where they'll send him to the frontlines," he told AFP. "The humanitarian situation is more and more desperate and it's hard to find food," he added.

No aid has entered east Aleppo for weeks, and international agencies have warned that residents there risk starvation.

The UN voiced provisional support for the humanitarian corridors, but its Syria envoy Staffan de Mistura urged that the body be allowed to take charge of the routes.

"Our suggestion to Russia is to actually leave the corridors being established at their initiative to us," he said. "How can you expect people to want to walk through a corridor, thousands of them, while there is shelling, bombing, fighting?"

On Saturday, regime war planes continued to hit opposition positions, with the Observatory reporting air strikes on two rebel-held areas on the outskirts of Aleppo.

The group also reported clashes in the two neighbourhoods, saying the government was attempting to forestall any rebel bid to bring in reinforcements to try to break the regime siege.

Syria's opposition has dismissed the humanitarian corridors initiative as a ploy and part of the government's bid to recapture all of Aleppo city. "Be clear - these 'corridors' are not for getting aid in, but driving people out," Basma Kodmani, a member of the opposition High Negotiations Commission, said Friday. "The brutal message to our people is: leave or starve."

Analyst Karim Bitar from the French think-tank IRIS, also said residents of the east faced "a terrible existential dilemma... between risking starvation or risking to die while fleeing."

More than 280,000 people have been killed in Syria's war which erupted five years ago.