Residents and rights groups have accused the government of using weapons that kill indiscriminately
* Syrian army pauses bombardment of town of Douma
* Insurgents set to leave rest of longtime enclave
* Thousands of fighters, families depart by bus (Adds rebels starting to depart)
BEIRUT, March 24 (Reuters) - Syrian rebels began pulling out of several towns in their former enclave of eastern Ghouta on Saturday, surrendering them to the government and leaving the besieged city of Douma as their last bastion there.
It comes after a month-long assault that devastated the already battered eastern Ghouta, an area of farmland and towns that was one of the first centres of the uprising in 2011 and the last major rebel stronghold near the capital Damascus.
Ten buses carrying fighters along with their families and other civilians started to leave the enclave after dark, the vanguard of a convoy heading into exile in northwestern Syria.
It follows the departure of thousands of others on Friday from the town of Harasta in a similar deal for insurgents to depart with light weapons in return for giving up their territory.
The buses queued at a crossing point before moving into the enclave along a road on the former front lines that had been cleared of barricades, debris and unexploded ordnance.
Some captives held by the insurgents were released and state television showed them leaving in a minibus.
The army was advancing into towns the rebels had retreated from in preparation for their exit, state television said. It broadcast pictures of the massive trenches and other fortifications the rebels were leaving behind.
It means only Douma is left of the opposition's eastern Ghouta enclave which a month ago the United Nations said was home to 400,000 people.
The army offensive to capture it, heralded by one of the heaviest bombardments in the seven-year conflict with warplanes, helicopters and artillery, has killed more than 1,600 people, said the Syrian Observatory for Human Rights, a war monitor.
Residents and rights groups have accused the government of using weapons that kill indiscriminately - inaccurate barrel bombs dropped from helicopters, chlorine gas and incendiary material that sets raging fires.
Syrian President Bashar al-Assad and his close ally Russia, which has helped his air campaign, have denied using all those weapons and say their offensive was needed to end the rule of Islamist militants over civilians.
About 7,000 people - fighters along with family members and other civilians who do not wish to come back under Assad's rule - were to leave the towns of Zamalka, Arbin, Ein Terma and Jobar starting on Saturday, rebels and state media said.
They will go to Idlib province in the northwest - the destination for many such "evacuations" after sieges and ground offensives forced numerous rebel enclaves to surrender in the past two years.
It will not mean an end to their experience of war. Syrian military and Russian air raids on Idlib have increased in the past week, killing dozens of people.
Idlib is also unsettled by fighting between the rebel groups. On Saturday, an explosion at a headquarters for al Qaeda's former affiliate killed at least seven people and injured 25 others.
The Britain-based Observatory said there were also negotiations with the Jaish al-Islam rebel group that controls Douma to release prisoners.
Russia will guarantee that civilians who remain in the areas recaptured by Assad will not be prosecuted, rebels said on Friday. However, rights groups have said some men were forcibly conscripted after fleeing the fighting.
Wael Alwan, spokesman for the Failaq al-Rahman group that was dominant in Zamalka, Arbin, Ein Terma and Jobar, was quoted by al-Hadath television on Saturday as saying he did not trust Russia's guarantees.
A Russian military webcam at the al-Wafideen crossing point near Douma showed small groups of civilians continuing to flee the danger of further bombardment into government territory, carrying children and sacks of belongings.
Russia's military said more than 105,000 people had left eastern Ghouta, including over 700 on Saturday.
Tens of thousands have fled their homes in the past week as the bombardment of Douma intensified and refugees from other parts of Ghouta found the basement bomb shelters too full to take them. (Reporting by Angus McDowall Editing by Mark Heinrich and Dale Hudson)
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