A man pushes a cart past damaged buildings at the besieged town of Douma, Eastern Ghouta, Damascus, Syria March 5, 2018. (Photo: Reuters)

The Russian military has offered Syrian rebels safe passage out of eastern Ghouta, setting out a proposal to let the insurgents surrender their last major stronghold near Damascus to President Bashar al-Assad, which fighters have so far rejected.

The Russian defense ministry said rebels could leave with their families and personal weapons through a secure corridor out of eastern Ghouta, where Moscow-backed government forces have made rapid gains in a fierce assault.

The Russian proposal did not specify where the rebels would go, but the terms echo previous evacuation deals under which insurgents have ceded ground to Assad and departed to opposition-held territory in the north near the Turkish border.

“The Russian Reconciliation Centre guarantees the immunity of all rebel fighters who take the decision to leave eastern Ghouta with personal weapons and together with their families,” said the defense ministry statement. Vehicles would “be provided, and the entire route will be guarded”, it added.

United Nations Secretary-General Antonio Guterres, in a statement issued by a spokesman on Tuesday, voiced concern about attacks in eastern Ghouta which “reportedly claimed the lives of more than 100 people” on Monday, as well as reports of shelling of Damascus.

Hundreds of civilians have been killed in the besieged enclave of satellite towns and rural areas on the outskirts of Damascus in one of the fiercest bombing campaigns of the seven-year-old war.

The United Nations believes 400,000 people are trapped inside the enclave where food and medical supplies were already running out before the assault began with intense air strikes two weeks ago.