BEIRUT: Former rebel militiamen who switched sides and joined Syria’s regime forces are engaged in a fierce battle against Islamist insurgents near Damascus, sources said Sunday.

According to the Syrian Observatory for Human Rights, the pro-regime Wafaa Army launched its “fiercest battle yet” Saturday against Islam Army fighters near the rebel bastion of Douma, east of the capital.

“The fighting is ongoing now,” Observatory director Rami Abdel-Rahman told AFP Sunday.

The Wafaa Army was formed some three months ago, more than a year into a suffocating regime siege of the Eastern Ghouta area, which includes Douma.

President Bashar Assad’s regime “is financing and arming the Wafaa Army,” Abdel-Rahman said.

“Among its ranks are armed men who, after more than a year under siege, handed themselves in to the regime,” Abdel-Rahman told AFP.

“Because of the siege, some people prefer to evacuate their children and have a chance at survival, rather than stay put and die, either from hunger or because of the bombings.”

He said the new pro-regime militia offers “a way for fighters to be free both from the regime siege, and from [Islam Army chief] Zahran Alloush,” who is notorious for his abuses.

Tens of thousands of people trapped in the siege suffer from food and medical shortages, as well as deadly regime bombardment.

A source close to Assad’s regime and an Islam Army spokesman confirmed to AFP a battle was ongoing.

“The Wafaa Army was set up three months ago by people from Douma and former rebels,” the pro-government source said.

“Yesterday [Saturday] they attacked the Islam Army and killed 12 of its fighters.”

Clashes between the Islam Army and regular army forces were underway in other areas of the Ghouta suburbs one day after the militia announced a 72-hour deadline for the authorities to release detainees in exchange for a paramilitary fighter.

In a video posted to YouTube, Assad tells a family from Ghouta that he will help find their missing son.

The militia produces the man, Mazen Darwish, who confesses to being a pro-regime paramilitary fighter before his capture by the Islam Army.

A militia spokesman demands the regime trade 100 female detainees for Darwish, challenging the president to demonstrate his concern for Syrian citizens.