The United Nations was on Friday preparing to deliver aid to a rebel-held town east of Damascus, in the second distribution of assistance since a shaky truce began in Syria.

An official in the UN's humanitarian coordination office told AFP that a convoy of "food, nutrition, and medical supplies" was to be distributed to 20,000 people in Kafr Batna on Friday.

"The convoy has just left Damascus," the official said.

Kafr Batna is in the rebel bastion of Eastern Ghouta, which was hit by air strikes on Friday for the first time since the truce began early last Saturday.

Eastern Ghouta, besieged by pro-government forces since 2013, was regularly and heavily bombarded by the regime, but had been relatively calm since the ceasefire started.

The first delivery of humanitarian assistance under the truce took place on Monday in Moadamiyet al-Sham, an encircled opposition town southwest of the capital.

Non-food items such as blankets and hygiene supplies were delivered there.