HARBIN - Authorities in Northeast China's Heilongjiang province are conducting a survey to find the exact number of endangered Siberian tigers as their numbers may have increased.

Sun Haiyi, deputy head of the Wild Animals Research Institute of Heilongjiang, said the province had set up more than 20 monitoring sites. Information will be submitted to the country's relevant authorities.

"Since 2005, wild Siberian tigers have been spotted many times by monitoring cameras in Laoye Mountain and Wanda Mountain areas in Heilongjiang," Sun told Xinhua.

He estimated that the number of wild Siberian tigers might have increased thanks to the protection efforts in recent years. Dead tigers were also found in Wanda Mountain and Mishan area, he added.

Sun said the conservation of natural forests had contributed a lot to the restoration of the food chain of Siberian tigers.

According to a survey in 2006 and 2007, Heilongjiang has about 12 wild Siberian tigers while neighboring Jilin Province has eight to ten such tigers, the expert said.

Yang Lijuan, an official with the Dongfanghong Forestry Bureau in Heilongjiang, said the bureau would add six food supply sites, from the current four, for the prey of wild Siberian tigers this winter.

Such artificial feeding could increase the numbers of red deer and roes to ensure the food source for the Siberian tigers, Yang said.

Siberian tigers, one of the world's rarest animal species, mainly live in east Russia, northeast China and northern part of the Korean Peninsula. Some 500 Siberian tigers currently live in the wild.