BEIJING (AFP) – Authorities are investigating a Chinese zoo where three dozen animals including 13 rare Siberian tigers died recently, amid charges it was harvesting their parts, state media said Monday.

The probe of the zoo in the northeastern city of Shenyang will look at whether the animal parts were being used as ingredients in Chinese medicine and other products, Xinhua news agency said.

China banned the international trade in tiger bones and related products in 1993, and is a signatory to the Convention on International Trade in Endangered Species (CITES), which also bars such trade.

But such transactions exist as many tiger parts, such as penises and bones, are commonly believed to increase sexual potency or cure certain illnesses.

Xinhua quoted a manager at the Shenyang Forest Wildlife Zoo as saying that the carcasses of the dead tigers, 11 of which starved to death and two of which were shot after mauling a worker, have been cut up and put in cold storage.

But another unnamed zoo worker said the bones had been used to make tiger-bone liquor that was used to "serve important guests".

The deaths, which came to light as China celebrates the Lunar Year of the Tiger, have been blamed on a combination of inadequate funding, an unusually cold winter and poor general conditions at the facility, the China Daily said.

Zoo workers fed the tigers cheap chicken bones in recent months as funding dried up. On Sunday, the Shenyang government announced that it had allocated one million dollars to save surviving animals and fund the zoo.

Besides the tigers, 22 other animals have died, including rare species that are protected in China, among them a red-crowned crane, four stump-tailed macaques, and one brown bear.

The Shenyang government has a 15 percent share in the zoo, which is mainly privately owned.

China says it has nearly 6,000 tigers in captivity, but just 50 to 60 are left in the wild, including about 20 wild Siberian tigers.

In the 1980s, China set up tiger farms to try to preserve the big cats, intending to release some into the wild. But conservation groups say the farms are used to harvest ingredients for traditional Chinese medicine.