Rebels and government forces engaged in heavy shelling across frontlines on the outskirts of Damascus, testing Syria's fragile truce, a monitoring group said, confirming at least two fighters were killed.
Nearly two dozen rockets and grenades were fired near Jobar neighbourhood, in the eastern outskirts of the Damascus, the Britain-based Syrian Observatory for Human Rights said, adding that two shells fell in the Old City, controlled by the government.
Battles were taking place on at least two fronts, with government forces attacking rebel positions.
Syrian state television said the government's troops had foiled a rebel attack. Faylaq al-Rahman, an Islamic militia, in a message on their Twitter account said there were heavy battles in Jobar and that their fighters have inflicted casualties among the regime forces.
It was unclear who first violated the ceasefire, which has been in place since Monday. "This is a clear breach of the ceasefire," the head of the observatory Rami Abdel Rahman said.
On Thursday, the government said two civilians were killed, the first deaths since the ceasefire started. The Observatory also said three civilians were killed in rebel-held Idlib province, near the border with Turkey.
The truce, brokered by the United States and Russia, has been largely holding up despite breaches. Russia has blamed violations on the rebels, while the opposition accused President Bashar al-Assad’s forces of breaking the terms of the deal.
Jobar is part of Ghouta, which is largely held by rebels, including hardline Islamic factions. Al-Qaeda linked militants who have a presence in the area are not included in the ceasefire.
A large part of Jobar neighbourhood is in the hands of the opposition rebels, while a small part of it remains in the hands of regime forces.
In Aleppo, the Observatory also quoted activists as saying a church in the government-held western Aleppo was hit by shells fired by rebels.
Meanwhile, dozens of trucks carrying UN aid intended for hard to reach and besieged areas of Syria remain stuck at the Turkish border.
The United Nations Syria envoy Staffan de Mistura put most of the blame for the delay in aid delivery on the government of President Bashar al-Assad, which has not yet provided any so-called facilitation letters for the aid trucks to cross front lines.
Moscow and Washington are blaming each other for the delay in aid and negotiations are believed to be ongoing. The UN Security Council is set to meet later in the day in New York.
Rebels, further complicating matters, are opposed to humanitarian supplies being delivered through access routes controlled by the government, fearing it would help al-Assad's forces reimpose sieges in the future.