Burma says it has expanded the world's largest sanctuary to protect endangered tigers.

The government announced that the entire Hukaung Valley in the country's remote northern region will be declared a  Protected Tiger Area.  Scientists believe several hundred tigers are living in the protected area, which covers more than 17,000 square kilometers.  

The documents signed Tuesday more than triple the size of the wildlife sanctuary, which was created in 2004.  

Conservationists say Burma's decision is a major step in saving wild tigers, one of the world's most endangered species.

The number of tigers in the wild has plummeted from up to 100,000 a century ago to fewer than 3,000 today.

The remaining tiger populations live in small, isolated groups and are constantly threatened by illegal hunting.

Burmese Prime Minister Thein Sein and 16 cabinet ministers flew to the Hukaung Valley earlier this year to assess its conservation needs.

International groups have begun a campaign to rebuild tiger populations by 2022 - the next Year of the Tiger on the Chinese calendar. They say tiger populations can make a comeback if governments effectively address the poaching of the big cats and the animals they feed on, as well as the destruction of their habitat.