A 50-year-old American woman only known as Lisa, has been bitten by a panda cub at a research center in Sichuan province in southwest China.

According to Xinhua news agency, the woman's thumb was bitten by a panda cub in the Wolong Giant Panda Protection and Research Center where she works as a volunteer.

The report said, "She was wearing gloves and feeding the panda bamboo on Tuesday morning when suddenly, the panda bit into her thumb.

"When she cried out, the cub became excited and gripped more tightly. Lisa finally managed to wrench herself free."

The report said that about 20 percent of the thumb had been bitten off.

Zhang Hemin, director for the center said they have been recruiting volunteers since 2004 with work lasting from one day to more than a month. Volunteers prepare food, feed pandas under supervision of professional keepers, her said.

More than 1,200 volunteers from America, Japan, Switzerland, France and Spain have already worked in the center.