Botswana, the world's largest diamond mine producer, says it will cut output by more than half this year because of low gem demand.

Debswana, the company jointly owned by the Botswana government and De Beers, plans to produce 15 million carats of diamonds this year, compared to 33.6 million carats in 2008, the BBC said. Diamonds decorate not only jewelry, but also industrial cutting tools.

The announcement came after the state diamond trading firm DTCB said it could only sell between 18 and 20 million carats. In February, Debswana had said it would close two mines for the rest of 2009.

The mining industry in Botswana has cut 4,500 jobs as global demand for diamonds has fallen.

Debswana produces close to a quarter of the world's output.