BEIRUT, Lebanon — Pro-government forces in Syria have conducted their worst bombardment in years of rebel-held suburbs east of the capital, killing nearly 100 people, emergency workers and monitors said on Tuesday.
As forces loyal to President Bashar al-Assad carried out dozens of airstrikes and fired hundreds of rockets on Monday at the enclave outside Damascus, known as eastern Ghouta, residents and emergency medical workers posted a cascade of alarming images: Five children found dead in the rubble, along with their parents. Families huddling in basements and dugout shelters. An ambulance crew loading a patient, then fleeing moments before an explosion almost hit them.
The Syrian Observatory for Human Rights, a Britain-based war monitoring group, said that Monday was the deadliest day in the area in three years. The United Nations estimates that there are nearly 400,000 people in eastern Ghouta.
Five medical facilities were damaged in attacks overnight, and a medical worker was killed, according to doctors working at hospitals supported by the Syrian American Medical Society. “Such targeting of innocent civilians and infrastructure must stop now,” Panos Moumtzis, the United Nations regional humanitarian coordinator for the Syria crisis, said in a statement.
The Syrian government and one of its major allies, Russia, have escalated an aerial campaign to subdue the rebel-held area, a cluster of working-class suburbs and farms that has been besieged for years, and as pro-government forces gather nearby for a possible ground assault.
The enclave is one of the last major areas held by insurgents fighting the Assad government, and controls crucial territory adjacent to the capital. Rebels based there have occasionally shelled government-held areas of Damascus, escalating their attacks in recent weeks.
Gen. Suheil al-Hassan, the leader of the government’s Tiger Force that has crisscrossed the country for major battles, said in a video shared by pro-government social media accounts that he would attack without mercy. The video also showed military vehicles said to be massing nearby.
“I promise, I will teach them a lesson, in combat and in fire,” General Hassan said. “You won’t find a rescuer. And if you do, you will be rescued with water like boiling oil. You’ll be rescued with blood.”
Residents described the events as more like an all-out attack on civilians and infrastructure to force a surrender, a tactic used in previous battles across Syria.
The government argues alternately that there are few civilians in eastern Ghouta and that those who remain are being held as human shields.
“We are still alive, we can’t walk outside the house, even a few meters,” Tareq al-Dimashqi, who lives in the area with his wife and five-month-old baby, said in an interview. “We might die any moment — you don’t know where the rockets might come from and end our lives.”
Referring to his daughter, whom he calls Loulou, after the 1950s actress Gina Lollobrigida, he added: “I have only this baby, and we can’t find food for her.”
“We have no other choice except resisting until the last moment,” he said. “Death and life became equal to me.”
Many in eastern Ghouta have been hiding in shelters. Shadi Jad, the father of a three-week-old, said the infant had not seen the sun or been exposed to fresh air in 48 hours.
“We have a small window in our shelter,” he said. “I bring him close to the window just for seconds, to get some warmth from the sunlight.”
Wassim Khatib, a resident reached by video chat, said that recent negotiations for hard-line insurgents to leave the area had failed.
“Civilians were never allowed to leave,” he said, looking pale and exhausted. “If the regime wanted the civilians to be evacuated, they could have announced that or at least dropped leaflets.”
Until last year, tunnels provided a way for goods and people to enter and leave the besieged enclave, but smuggling fees were always high. Movement has become nearly impossible since government forces took over surrounding territory. Roads were opened briefly, but only government employees were allowed to go back and forth, residents said.
The Union of Medical Care and Relief Organizations, a consortium of aid groups working in Syria, said that 97 people had died since Monday. Syria Civil Defense, an organization of rescue workers known as the White Helmets, put the toll at 89 as of noon Tuesday, counting only casualties that its volunteers had confirmed. The group added that 400 people were wounded, many of them women and children.
They also counted 66 airstrikes and at least 466 rocket attacks.
The government-run news agency Sana said that reports of an escalation in eastern Ghouta were “lies, deception, and fabrications” used by “terrorist organizations and their sponsors within capital cities conspiring against Syrians.” It also referred to the White Helmets as terrorists and “tools” aiming “to target countries that reject American dictates.”
The White Helmets receive some funding from the United States and European countries. The Syrian government does not provide rescue services in insurgent-held areas.
On Tuesday, new shelling sent dozens of people to hospitals in the area.
Mr. Moumtzis of the United Nations called on all parties to “strictly adhere to their obligations under international humanitarian law to take all feasible measures to protect civilians from harm, including the prohibition on launching of indiscriminate attacks and principles of proportionality and precautions.”
“The humanitarian situation of civilians in East Ghouta is spiraling out of control,” he added. “It’s imperative to end this senseless human suffering now.”