Beijing, Dec 7 (IANS): A medical school in China's Shaanxi province has been criticised after it was found to have discarded dogs on the rooftop of its teaching building after conducting experiments on them, the media reported on Monday.

An 18-second-long video uploaded on social media showed several dogs covered in bruises and bleeding from surgical wounds discarded among piles of medical products on the rooftop of a teaching building at Xi'an Medical University. The dogs' mouths were tied shut, and some of them were still alive.

"The dogs in the video were removed from the rooftop when we got there on Sunday morning. But there are still 19 dogs caged on the rooftop, and many of them are skinny and shaking in the wind," Jiang Hong, head of a Xi'an-based animal protection group, told the Global Times.

Jiang said officials from the university told volunteers that the school bought dogs for medical experiments from a dog farm, and students performed different intestinal surgeries on the dogs seen in the video.

A teacher from the university said that the institute needs to use about 200 dogs annually for experiments, a smaller number than many other medical schools.

A student said that the dogs are usually kept under anaesthesia for different experiments before mercy killing.

According to animal testing regulations issued in 2011, organisations and individuals should get approval from local health authorities before performing tests, and are required to treat animals with care. Farms for animals used as test subjects should also get approval from related departments and must comply with regular checks.