BEIRUT — Syrian troops began a ground offensive under the cover of airstrikes on rebel-held areas outside the capital Damascus on Friday after a 10-day truce collapsed over disagreement regarding evacuation of opposition fighters.

The new wave of violence left at least 36 people dead, including women and children, according to state media and opposition activists.

By sunset Friday, artillery pieces, multiple rocket launchers and warplanes intensely pounded the city of Douma, which is home to tens of thousands of people. Live TV footage showed thick smoke billowing from different parts of the city as airstrikes create huge clouds of dust.

Douma is the largest city in eastern Ghouta. Government forces captured the entire region except for the city in a crushing offensive in February and March. The city is a stronghold of the Saudi-backed Army of Islam.

Violence resumed in and around Douma on Friday afternoon after the Army of Islam placed new conditions on an evacuation deal that saw hundreds of fighters and civilians leave earlier this week.

The intense bombardment could be meant to pressure the insurgent group to evacuate the city as many fear that the death toll could be high in an all-out battle to retake the town. Army of Islam has thousands of well-armed fighters in Douma.

Before the fighting resumed, helicopters earlier Friday dropped leaflets on Douma saying rebels should either leave to the northern town of Jarablus or hand over their weapons and receive amnesty with Russian and Syrian government guarantees that would include not drafting young men to the military until after six to 10 months.

The leaflets also called on civilians to stay, saying their safety would be guaranteed by Russian Military Police deployed outside Douma.

Opposition activists and state media said there are divisions within the Army of Islam between moderate members who want to leave Douma and followers of the hard-line religious chief of the group, Abu Abdul-Rahman al-Kaaka, who rejects any deal with the government and wants to fight.

Top Army of Islam official Mohammed Alloush denied in an interview with the Dubai-based Al-Arabiya TV that there are disagreements within the group, saying that what they are concerned about is the safety of civilians in Douma.

He added that the violence came a day before a new round of negotiations with the Russians during which they were supposed to respond to an offer put forward by the Army of Islam. He did not give details of the proposal.

Nearly 50 airstrikes on Douma as of Friday afternoon killed at least 32 people, including children, according to the Britain-based Syrian Observatory for Human Rights. Douma-based activist Haitham Bakkar said at least 35 people were killed.

“We are being wiped out right now. We are being bombarded with barrel bombs and rocket launchers,” Bakkar said via text message from Douma. “The town is overcrowded and many people have no place to hide.”

Syrian state TV said several airstrikes hit Douma after members of the Army of Islam rebel group shelled government-held areas nearby killing and wounding a number of people.

State news agency SANA reported Friday that the shelling on government-held Damascus killed four and wounded 22 others.