Assad forces are said to be close to splitting the rebel enclave in two

A member of the Syrian Civil Defence White Helmets group carries a child wounded in Eastern Ghouta. Photo / AP

Syrian President Bashar al-Assad says a military operation against the Eastern Ghouta area near Damascus would continue while civilians would be allowed to leave the rebel-held area.

"There is no contradiction between a truce and combat operations," he said.

"The progress achieved yesterday and the day before in Ghouta by the Syrian Arab Army was made during this truce," Assad said in broadcast comments to journalists.

"Therefore we must continue with the operation in parallel with opening the way for civilians to leave."

He was referring to a daily humanitarian ceasefire called by Russia from 9am to 2pm local time, which the US has dismissed as "a joke".

Thousands of civilians have fled the advances by the Syrian forces in Eastern Ghouta in the past two days, a war monitor and a resident said, as Damascus makes rapid gains against the last major rebel enclave near the capital.

Government forces need to advance just a few more kilometres further to split the enclave in two, said a commander in the alliance that backs Assad.

The Syrian Observatory for Human Rights said government forces had seized around a quarter of Eastern Ghouta in a ground assault that began on February 27, building on a ferocious air and artillery bombardment that has killed hundreds.

One of the main insurgent groups in Eastern Ghouta, Jaish al-Islam, said the "scorched earth policy" had forced rebels to retreat and regroup, but vowed to recover lost territory.

"We keep repeating the same mistake. Srebrenica, Rwanda, Darfur and now Syria."

A Syrian-American doctor travels to a hospital on the Turkey-Syria border determined to help victims of the ongoing war. Full doc: https://t.co/3CxCqDvxq2 pic.twitter.com/KRjbxhC0TW

— AJWitness (@AJWitness) March 4, 2018

- Reuters, AAP