LA PAZ, Sept. 15 (Xinhua) -- Authorities in Bolivia on Monday confirmed that four people were killed and 11 more injured in a clash happening in central Bolivia's El Abra prison over the weekend.

"There was a shooting," the Bolivian Information Agency (ABI) reported, quoting Denis Mejia, the director of prisons in Cochabamba department, as saying.

The fighting broke out around 10 p.m. Sunday at the El Abra prison, after a sudden blackout interrupted a feast held to mark the festival of the Virgin of Urcupina. El Abra prison is located five kilometers away from the department capital city, Cochabamba.

No other information concerning details of the prison clash is available.

The authorities are investigating the cause of the clash.