Caroline Hidayat, 24, a doctor’s assistant from the city, said: “Most doctors in Syria do not treat Syrians because there are no hospitals left. People are dying from lack of medical supplies and care.”

But with many hospitals running out of treatment rooms, doctors who are able to travel on their own have found work in Turkey.

As of Thursday, there was a shortage of a number of critical facilities in Aleppo, including those treating cancer, organ transplant and cardiac procedures, Hidayat said.

“It’s bad because now Syrians wait longer to get access to specialist treatment for their cancer, kidney and heart failure,” she said. “The situation is getting worse by the day.”

Aleppo’s hospitals have been hit twice since fighting started. The first time, two years ago, nearly 80 percent of the city was destroyed, although rebel soldiers recaptured most of the city shortly afterwards.

The second time was in March, when President Bashar al-Assad’s forces launched a major assault on opposition-held east Aleppo.

More than 100,000 people have been evacuated from the city since then, but it has remained open for civilians. Many hospitals remain closed or run on a volunteer basis.

One of the most severely damaged hospitals is known as the “Centre for Care and Treatment” or “Chemical Hospital” because of the chemical agents discovered in its basement.

But even that centre was destroyed by shells, rockets and a large-scale air strike on April 6. The hospital had just been upgraded, and residents said hospitals run on volunteer hours were still working there.

One patient, a doctor who gives polio vaccine to children in opposition territory, was able to get the vaccine on Friday but couldn’t go to work because he had no access to another hospital.

“There is no medical equipment that protects people from chemical attacks,” he said. “We lost so many cases here, including children under two years old.”

He said he got one shot of the vaccine, but lost his wife to the chemical. Then he suffered respiratory problems.

A nurse who works with some of the injured in the northern city of Aleppo said that there were about 7,000 people who had become seriously ill due to the bombings and attacks.

“This year, hospitals were targeted by regime and Russia-backed terrorists. They burned clinics and turned hospitals into rubble,” said the nurse,