Airstrikes pound rebel-held Damascus suburb, leaving more than 200 dead

LONDON -- The Syrian government and its allied forces pounded a besieged rebel-held Damascus suburb on Tuesday, killing dozens of civilians just a day after the enclave's highest death toll in three years.

Airstrikes and shelling have killed at least 210 civilians, including 54 children, since Sunday night, the Syrian Observatory for Human Rights, a U.K.-based monitoring group, said. On Tuesday, at least 66 civilians were killed.

On Monday alone, at least 127 civilians lost their lives, the Syrian Observatory for Human Rights said.

"Every day people die and we're used to it," Nour Adam, 22, a media activist in Eastern Ghouta who asked that his real last name be withheld out of concern for the safety of family members in government territory, told ABC News via Skype. "But people think we are numbers. Actually, we are humans."

During the interview the sound of an explosion could be heard in the background.

The recent surge in violence in Eastern Ghouta, which has been besieged by the Syrian government since 2013, is part of President Bashar al-Assad's campaign to seize Syria's last remaining opposition-held territories.

"The Syrian government is attacking all areas with all kinds of weapons -- known and unknown weapons," Siraj Mahmoud, head of media for the White Helmets civil defense rescue force, which operates in rebel-held areas in Syria, told ABC News.

"Warplanes don't leave the sky at all. Today, we can't say that we have any safe areas left in Eastern Ghouta," Mahmoud, who works under a pseudonym, added.

The Syrian foreign ministry said that militants in Eastern Ghouta fired shells at Damascus on Tuesday, killing six civilians, according to the state news agency SANA.

An estimated 400,000 people are trapped in Eastern Ghouta with little access to food, water, fuel, electricity and health care. Many of them have left their homes and moved into underground shelters, where they spend their days and nights in hiding due to the intensity of the strikes.

Save the Children said on Tuesday that 4,100 families now live in underground basements and shelters. More than half are without water, sanitation or ventilation systems, according to local aid workers.

"The bombing has been relentless, and children are dying by the hour," said Sonia Khush, Save the Children's Syria response director, in a statement. "These families have nowhere left to run - they are boxed in and being pounded day and night."

The aid agency said that in some parts of Eastern Ghouta, the destruction is worse than it was at the height of the Syrian government's offensive against Aleppo in 2016, "yet with only a tiny fraction of the global attention and outrage."

The United Nations warned on Tuesday that the humanitarian situation in Eastern Ghouta is "spiraling out of control" and that lack of access to the besieged enclave has kept aid away, leading to severe food shortages and a sharp rise in food prices. Malnutrition rates have now reached unprecedented levels, the U.N. said.

"I am deeply alarmed by the extreme escalation in hostilities in East Ghouta," Panos Moumtzis, U.N. regional humanitarian coordinator for the Syria crisis, said in a statement.