GENEVA – Syrian government forces are systematically attacking hospitals and medical staff and denying treatment to the sick and wounded from opposition-controlled or affiliated areas, the U.N. investigators said Friday in a new report that also detailed the use of hospitals as torture centers by military intelligence.

"The denial of medical care as a weapon of war is a distinct and chilling reality of the war in Syria," the U.N. Commission of Inquiry monitoring human rights in Syria said in its report. The panel said pro-government forces carried out such attacks "as a matter of policy," but it also documented instances of attacks on hospitals by opposition forces.

The four-member panel said it published these findings two days after a broader report on war crimes in Syria to draw attention to what they called "an enduring and underreported trend" in the conflict. "By rejecting the irrefutable and universally accepted principle that those wounded in hostilities must be treated, the parties to the conflict in Syria are setting a dangerous precedent," the panel warned.

The report cited a string of attacks on hospitals that were shelled by artillery or bombed by jets, often after aerial reconnaissance by helicopters. A public hospital in the northern city of Aleppo came under fire from helicopters and was hit by rockets and a missile strike.

Flouted the laws of war

"These attacks injured and killed civilians receiving treatment in the hospital and medical personnel, significantly damaged the hospital's infrastructure and substantially reduced its ability to treat patients," the report said.

Rebel fighters from the Al Farouq Brigade attacked a national hospital as part of a broader offensive on the city of Homs in April 2012, making no effort to protect civilians or patients in the hospital, which was later largely destroyed in a counterattack by government aircraft, the panel said.

Both sides have flouted the laws of war by positioning troops, snipers and even tanks in or around medical facilities, exposing them to the danger of attack, according to the report.

It highlighted the targeting of medical personnel as "one of the most insidious trends" in Syria's civil war. "Government forces deliberately target medical personnel to gain military advantage by depriving the opposition and those perceived to support them of medical assistance for injuries sustained" the panel said.

The government "effectively criminalized" medical care to the opposition in anti-terrorism laws introduced in July 2012 but long before then, in the early days of protests against the government, security forces had cracked down on medical staff who provided treatment to demonstrators, the investigators said.

'Tortured to death'

Security forces carried out "a wave of arrests" of doctors and medical professionals in a hospital in the capital, Damascus, in April 2011 who resisted orders to deny medical treatment for injured protesters, and three doctors were later detained and tortured by Air Force Intelligence, an agency the investigators have previously identified as one of the government agencies most heavily involved in torture.

Doctors, surgeons, ambulance drivers and medical personnel seeking to aid the wounded or deliver medical supplies have been arrested, tortured, murdered or have disappeared. Patients, too, are among the targets. "In exploiting medical care to further strategic and military aims, government forces have engaged in agonizing cruelty against the sick and wounded," the report said, identifying a number of government intelligence agencies that have used hospitals as torture chambers.

Among these is Military Hospital No. 601 in Damascus where "detainees, including children, have been beaten, burned with cigarettes, and subjected to torture that exploits pre-existing injuries. Many patients have been tortured to death in this facility," the panel said.