Wildlife experts said enhanced protection measures gave hope to the protection of wild Siberian tigers in China-Russia border region, but human activities still disturb their free movement and habitation, a key to the survival of the highly endangered species.

"Wire fences (erected along the border) and railway construction block the free migration of wild Siberian tigers," Sun Quanhui, an expert with the Wildlife Conservation Society's (WCS's) China program, said Thursday at a conservation seminar in Hunchun in northeast China's Jilin Province.

Although China and Russia join hands to protect the species, there are just some narrow "corridors" for the Siberian tigers to cross the border, Sun said at the meeting, in which experts discussed transborder conservation of wildlife in Northeast Asia.

He expressed worries that the Dongning-Hunchun railway under construction could bring negative impact on the tigers' movement.

The 200-km-long railway will link Dongning county in Heilongjiang Province with Hunchun in the south, almost parallel to the China-Russia border.

"Most parts of the railway line run through forest areas where wild tigers have been frequently traced. The construction of the railway will affect free movement of the tigers," Sun said.

The Siberian tiger is a subspecies of tiger which once roamed in Russian Far East, eastern part of northeast China and northern part of the Democratic People's Republic of Korea.

Due to fragmentation of forests and poaching, only about 20 Siberian tigers are believed to live in wild in Jilin and Heilongjiang, while the population of wild tigers in neighboring Russia is estimated between 430 and 500.

The habitat for wild tigers has been recovering in recent years in the Chinese side following crackdowns on illegal poaching and with more nature reserves established.

In Hunchun Nature Reserve alone, the number of wild tigers rose from three to five in 2001 to five to seven this year.

It is estimated that, in 2022, the population of wild Siberian tiger in China would reach about 40, if habitat protection work goes well, said Zhu Chunquan, forest program director of WWF (World Wildlife Fund) China.

"We are planning to connect the 'isolated' nature reserves together to expand the range of living for wild tigers," said Qiao Heng, deputy director of the Jilin Provincial Department of Forestry.

Jilin and Russia signed an agreement in August, pledging to increase bilateral cooperation in expertise and equipment support, training and frequent exchange of conservation information.