BEIJING - Loggers in China's southwest are destroying sanctuaries home to endangered giant pandas, environmental group Greenpeace said in a report on Wednesday, defying efforts by conservationists and tougher forestry regulations.

Logging of more than 3,200 acres (1,295 hectares) of natural forest has threatened the habitats of rare plants and animals in the Sichuan Giant Panda Sanctuaries, Greenpeace found during a two-year investigation.

The sanctuaries are a UNESCO World Heritage site.

"These loopholes are allowing an area of nationally and internationally recognised significance to be exploited for profit, endangering local wildlife and global treasures, such as the iconic and rare giant panda," Greenpeace said in the report.

Developers have turned some areas of natural forest into "profitable plantations" by exploiting a loophole that allows reconstruction of forests, it added.

The investigation used tools such as remote sensing, spatial analysis and field surveys.

Forestry authorities in China did not immediately respond to a request for comment.

There are only about 1,600 giant pandas left in the wild, the World Wildlife Fund has said, citing Chinese government figures. About 300 more live in captivity.

The critically endangered animals native to China have an extremely low reproductive rate, particularly in captivity.