AZAZ, Syria -- The national hospital in the northeast Syrian town of Azaz opened just five years ago, but today it lies in ruins; government aircraft bombed an entire wing in late December.

In nearby Aleppo, a barrel bomb, most likely shoved from a government helicopter, had forced the closing of the Dar al Shifa hospital in November.

Those are just two examples of the heavy toll taken on Syria’s hospitals, both public and private, in the nearly two years of war that’s ravaged this country. Half of the hospitals are now out of service, according to the Syrian government.

International officials decry what they say is a government campaign against health care facilities and medical professionals that constitutes a war crime. Humanitarian aid workers call it the worst health care crisis on Earth. Legal experts say the assault on doctors and medical facilities has set back the clock of humanitarian standards by 150 years.

“This targeting of medical facilities is greater than we’ve seen in modern warfare,” said Stephen Rapp, the U.S. ambassador-at-large for global criminal justice. The Syrian government, he said, is “conducting a campaign with total disregard for human life and a deliberate effort to harm civilians.”

The toll goes beyond the buildings themselves, a special U.N. commission reported last week, citing examples of government hospitals’ rejecting wounded civilians – even children – if they’re thought to be opposition supporters. Field hospitals set up to treat wounded rebels also are routinely targeted, the commission reported, a violation of international law that dates to the first Geneva Convention in 1864, when European nations banned attacks on wounded soldiers, military hospitals and ambulances.

In Azaz, a town close to the Turkish border, the Syrian army seized the 200-bed national hospital last June and turned it into a military base, stationing tanks and other armored vehicles on the grounds, the U.N. commission reported. An eyewitness told the commission that snipers were on the roof.

Rebels fighting to overthrow President Bashar Assad captured the town about a month later and attempted to restore the hospital to its earlier purpose, said Muhammed Karkupi, a press officer at a nearby camp for people who’ve fled their homes. Those plans were never fully realized, however, in large part because the hospital was too near a government military base, and the government bombed it on Dec. 31.

According to Karkupi, a rebel leader, Ammar Bebekhi of the North Storm brigade, had been wounded in a battle to control a nearby air base, and the army may have eavesdropped on fighters saying over a walkie-talkie that he was being taken to a hospital. Not long afterward, a combat plane flew overhead and bombed the hospital twice. An entire wing was devastated, and windows were blown out all over the hospital. The rebel leader survived because he’d been taken to a different hospital.

Last week’s U.N. report, citing interviews with refugees, listed more than a dozen attacks on hospitals and field clinics since last summer, almost all on facilities that had been treating wounded opposition fighters. It said hospitals and medical units had been targeted “to gain military advantage by depriving anti-government armed groups and those perceived to support them of medical assistance.”