At least 50 people have been killed in a prison riot in western Venezuela, BBC News reported.

The riot was triggered when local media broadcast news that soldiers had been sent to Uribana prison in Barquisimeto to search for weapons, Prisons Minister Iris Varela said.

Hospital director Ruy Medina said that some 90 people were injured, mostly from gunshot wounds. The dead are thought to include inmates, guards and prison workers.

Carlos Nieto Palma, coordinator of the non-governmental organization "A Window to Freedom" that defends Venezuelan prisoners' rights, told BBC Mundo that the death toll could rise. "What should have been a normal procedure in any prison ended in a clash between National Guard [soldiers] and inmates," he said.

He added that his organization classed Uribana prison as the most dangerous in the country, on the basis of the number of violent incidents recorded there.

Venezuela's prisons are blighted by overcrowding and the proliferation of weapons and drugs. According to the BBC, it appears that prisoners who had heard about the search in advance from news reports were waiting for the National Guard when they arrived.

It is thought that the search was aimed at disarming gangs within the prison and had been planned for some time.

There has been no official account of the incident or confirmation of the number of casualties, but the government says it will carry out a full investigation.