MOSCOW (AP) — Russian Prime Minister Dmitry Medvedev said on Tuesday that authorities will shut down a paper mill on the shores of Lake Baikal, which environmentalists say is a major pollutant threatening one of the world's largest fresh water lakes.

Authorities first closed the Baikal Pulp and Paper Mill in 2008 before it re-opened in 2010. Then Prime Minister Vladimir Putin stressed then that the employment of the mill's 1,500 workers in the eastern Siberia town of Baikalsk superseded ecological concerns. The plant's management admitted that the restart was just a temporary measure to buy time to work up an employment plan. Some 14,000 people live in the town.

Environmentalists said that the mill threatens the lake's unique species of plants and animals. Lake Baikal, which contains more fresh water than all of America's Great Lakes combined and is the world's largest freshwater lake by volume, is home to some 1,500 species of plants and animals found nowhere else in the world.

Medvedev, who was visiting Lake Baikal on Tuesday, said "there's no way back" on the decision to close the plant, Russian news agencies reported.

"It's time to muster up the courage and make responsible decisions," he was quoted by the Interfax news agency as saying.

Medvedev pledged nearly $1 billion toward the development of the area. He also suggested introducing tax breaks to spur tourism on Baikal's shores.