Major Hospital in Aleppo, Syria, Bombed for Third Time in Days Attacks have closed the largest trauma and ICU center in the Syrian city.

 LONDON -- Bombs struck one of the largest hospitals in east Aleppo, Syria, today for at least the third time in as many days. The hospital is now completely destroyed, according to the Syrian American Medical Society (SAMS), which supports the facility. Only five hospitals remain operational in the besieged part of Aleppo.

The hospital, known as M10, operates underground and is the largest trauma and ICU center in eastern Aleppo. It was hit by a bunker-buster bomb that can destroy underground structures and hurt people sheltering in basements, said SAMS.

The same hospital was also attacked several times Saturday and again last Wednesday. Every time, it was forced to shut down due to extensive damage. The hospital was also closed at the time of today’s attack, but staff and technicians were inside, trying to repair the facility and protect the equipment, according to SAMS.

“Our initial reports are telling us that three maintenance workers were killed and other staff remain under the rubble,” SAMS spokesperson Caroline Philhower told ABC News. “We are still learning more information as the attack was very recent.”

SAMS later confirmed that a bunker-buster bomb landed in front of the entrance, killing three maintenance workers and injuring a nurse and an ambulance driver.

On Saturday morning, the same hospital was hit by seven airstrikes, including at least two barrel bombs, killing two patients and injuring 13, according to SAMS, which also noted that the hospital was intentionally targeted and was forced to close. Patients were transferred to other hospitals. Warplanes continued to drop bombs, including phosphorus and cluster bombs, until 1 a.m. local time, forcing medical personnel to seek refuge in a nearby shelter, according to SAMS.

A doctor at another east Aleppo hospital that has received many patients from medical facilities that are out of service due to attacks said they are even busier than usual.

“At any moment, we can receive wounded and injured in addition to the patients we have already,” Hamza Khatib, the doctor, told ABC News.

Fewer than 30 doctors are now left working in Aleppo city, down from 35 several days ago, a senior official of the United Nations health agency said. According to Physicians for Human Rights, 95 percent of medical personnel who were in Aleppo before the war have fled, been detained, or were killed.

“There has been a reduction in the number of health workers able to stay at their posts, and those who did are exhausted, drained physically and emotionally,” Rick Brennan, the Director of Emergency Risk Management and Humanitarian Response of the World Health Organization, told reporters in Geneva on Friday.

Around 270,000 people are living under siege in east Aleppo, Brennan said. The blockade means the eastern part of the city lacks medical supplies, equipment and fuel to the remaining health facilities, and no patients are able to get out. Children and other civilians are being treated on the floor in hospital corridors and there are not enough beds in the intensive care units, Brennan said.

More than 800 injured people in Aleppo, including many children, a large number of them with life-threatening injuries, are in need of access to urgent health care, according to WHO, which has called for them to be let out of the besieged area and treated.

The Syrian military has urged rebels in east Aleppo to surrender. Syrian and Russian airstrikes on Aleppo intensified after the Syrian military declared an offensive against eastern Aleppo on Sept. 22 -- a few days after announcing that a U.S.-Russia-brokered ceasefire had ended. Locals and activists say chemical weapons, bunker-buster bombs and other types of explosives have been used, killing children, health personnel, aid workers and members of the Syrian Civil Defense.