Pro-government forces have intensified their assault on rebel-held suburbs of the Syrian capital, activists said, a day after the rebels beat back an attempted government advance, killing several soldiers.

The fighting in Damascus threw into sharp relief the fragility of a ceasefire that was supposed to bring calm to the besieged enclave inhabited by 400,000 people.

Opposition media activist Anas al-Dimashqi said government air raids and artillery fire have reached a rate of 60 to 70 strikes per day on areas held by the Faylaq al-Rahman rebel faction, which was not party to the ceasefire brokered by Egypt and Russia and signed in Cairo on July 22.

Air strikes on Ein Terma and Zamalka in Ghouta blasted debris hundreds of feet into the air, as seen in footage posted by the Ghouta Media Centre on social media. The opposition-affiliated centre said one civilian was killed and several wounded.

But mortars also fell on Douma, al-Rayhan and Housh al-Douahira, towns and villages held by the Islam Army faction, which is party to the ceasefire, according to Mr al-Dimashqi and the Britain-based Syrian Observatory for Human Rights monitoring group.

The Observatory said rebels killed nine soldiers and captured at least one fighting for the Syrian army’s vaunted 4th Division, in battle on Monday. It said the bombardment continued on Tuesday.

“What kind of ceasefire is this?” said Observatory director Rami Abdurrahman. “I don’t consider this a ceasefire.”

Faylaq al-Rahman said it came under attack by the Islam Army over the weekend.

It said in a separate statement published on Sunday that it would agree to a ceasefire that does not “compromise the principles of the revolution”, but said it was not consulted for the Cairo agreement.

Ein Terma, once home to 40,000 residents, has been largely vacated, according to Mohammad al-Boush, another media activist in Ghouta.

He said civilians across the Ghouta region are in dire need of food and fuel, particularly after government forces seized the Qaboun and Barzeh neighbourhoods in north-east Damascus in May. The two neighbourhoods were hubs for smuggling supplies into the Ghouta region.

Meanwhile, a powerful Iraqi Shiite militia said at least 40 of its fighters were killed in an attack the previous day on its positions across the border in Syria.

The militia blamed the US-led coalition for the assault but the Islamic State group claimed its fighters targeted the militiamen.

The deputy head of the militia, known as Kattaib Sayeed al-Shuhadaa, accused US forces of carrying out the assault.