A Siberian tiger has given birth to sextuplets at a zoo in east China's Zhejiang Province, boosting the endangered species' population, which had been estimated at less than 400 in the wild, local zoo officials said.

The No. 166 tiger at Hangzhou Wild Animals' Park delivered her first cub under close monitoring at about 7:40 a.m. Sunday and the delivery lasted for about four hours. All the baby tigers survived, according to the zoo.

"We just couldn't believe it!" a zoo keeper said. "Giving birth to six is extremely rare."

It is the third birth by the four-year-old Siberian tiger who had delivered seven cubs before and six survived, according to the zoo.

The Siberian tiger is one of the world's rarest mammals. Fewer than 400 are believed to survive in the wild, about 20 of them in China and the rest in Russia.

Zookeepers had to put three baby tigers into anther cage as the parent tiger has only four nipples for four cubs thus putting the other two cubs on starvation threat.

The three separated cubs are being fed with baby bottles and now urgently need fresh dog milk with nutrition similar to the tiger, the zoo officials said.

A local newspaper has opened a hotline to find substitute dog "mothers" for the cubs.

(Xinhua News Agency March 2, 2004)