Rebel-held parts of Ghouta are under a crippling government siege that has made food and medicine difficult to access for its estimated 400,000 residents.
“There are more than 1,000 people who require medical evacuations. The majority of them are women and children,” said Linda Tom, from the UN’s humanitarian coordination office (OCHA) in Damascus.
According to numbers provided on Monday by OCHA, they include more than 77 “priority cases.”
Since February 18, Syrian troops have been waging a fierce offensive on rebels in Eastern Ghouta, the last opposition bastion on the outskirts of Damascus.
OCHA said 28 health facilities in Eastern Ghouta had been hit in the assault, and nine health workers killed.
Rebels have also fired rockets onto the capital.
According to OCHA, five hospitals and 26 schools in Damascus have been hit.
The UN Security Council on February 24 demanded a month-long cease-fire in Eastern Ghouta that would allow for aid deliveries and medical evacuations.
Since the cease-fire resolution was passed, two convoys of humanitarian assistance have entered the besieged area, but no medical evacuations have taken place.
Meanwhile, UNICEF has said that children are at more risk than ever in Syria's devastating conflict, the UN said Monday as the war approached its eighth year.
The UN children's agency UNICEF reported a 50 percent increase in the number of children killed in the conflict last year compared to the previous year.
"In 2017, extreme and indiscriminate violence killed the highest ever number of children -- 50 percent more than 2016," it said, adding that 2018 was off to an even worse start.
More than 200 children have been killed in bombardment of the rebel-held enclave of Eastern Ghouta by Syrian regime and allied forces since February, according to the Syrian Observatory for Human Rights.