Eighteen people have been killed in a diamond mine in central Democratic Republic of Congo, union officials said.

Celestin Kubela, the head of the local mining authority in Kasai province, said that the victims, who were all illegal miners, are thought to have knocked away a pit prop deep underground.

Jean-Marie Kabuya, a local union official, said on Thursday:"Eighteen have died and there is only one survivor."

Seven of the 18 bodies have been recovered, Kubela said.

Abandoned mine

The mine had been abandoned and its holding company had closed since November last year, hamstrung by outdated equipment and further hit by the fall in global diamond prices.

The company, which employed 5,000 people, produced an average of six million carats annually at the start of the decade.

Production fell to one million carats in 2007 and less than 500,000 carats
last year.

The state holds an 80 per cent stake in the firm. The remaining 20 per cent belongs to Mwana Africa, a South African company.