As the number of physicians in Syria steadily decrease, healthcare experts from international agencies seek intervention to protect the remaining medical workers serving in the country's war zone. According to a report by The Telegraph , an open letter published by the world's leading general medical journal, The Lancet, claimed Syrian rebels are largely to blame for the disintegration of the country's medical infrastructure. "Systematic assaults on medical professionals, facilities and patients are breaking Syria's health-care system and making it nearly impossible for civilians to receive essential medical services," the letter said. Some medical experts, including the chiefs of major international aid agencies and three Nobel Prize winners, demanded that "medical colleagues in Syria be allowed and supported to treat patients, save lives, and alleviate suffering without the fear of attacks or reprisals." The Violations Documentation Center estimates that 469 health workers are currently imprisoned, and about 15,000 doctors have been forced to flee abroad, according to the Council on Foreign Relations. As the open letter highlighted, of the 5,000 physicians in Aleppo before the conflict started, only 36 remain. The records released by the World Health organization reveal that 37 percent of Syrian hospitals have been destroyed, and a further 20 percent severely damaged during the Syrian civil war. Syrian civilians are forced to go to primitive field hospitals, often run in people's homes and by local volunteers with only the most basic of medicines and training. The volunteers treating these patients have been forced to smuggle medicines into areas besieged by the Syrian regime or by armed rebels. They use these areas, in which there are a lack of medical attention for civilians, as a means of putting pressure on their enemy. The letter calls on all combatants in Syria to spare hospitals and clinics and to allow doctors and nurses to operate freely in what they call "the worst humanitarian crises since the end of the Cold War." "We call on the Syrian government and all armed parties to refrain from attacking hospitals, ambulances, medical facilities and supplies, health professionals and patients; allow access to treatment for any patient; and hold perpetrators of such violations accountable according to internationally recognized legal standards," the letter said.