Six people have died and another 15 have been injured during a riot in a Venezuelan prison, officials say.

The violence broke out at Los Teques prison, near the capital Caracas, on Sunday, during visiting hours for relatives.

It was not immediately known what sparked the incident.

Violence is common in Venezuela's prisons, where rival groups sometimes fight for control of cell blocks or the sale of drugs.

Prison official Consuelo Serrada said that eight of the injured inmates at Los Teques were taken to hospital, while the rest were treated at the jail, according to Venezuela's state media.

The official added that the authorities had the situation under control.