Caracas (Venezuela), May 2 (AP) A riot erupted at a prison in central Venezuela on Friday, leaving about 20 casualties, including a National Guard officer who was wounded by an explosion and the warden, who suffered a knife wound, authorities said.

Officials indicated there were some deaths, but gave no figures.

The violence at the Llanos Penitentiary Center resulted in an armed confrontation between inmates and guards, lawmaker María Beatriz Martínez told The Associated Press.

It was unclear what sparked the violent unrest.

Martínez said she did not have exact figures on the dead and injured at the prison, which is in the city of Guanare, 450 kilometers (280 miles) south-west of the capital of Caracas.

The National Guard officer was injured by a grenade explosion, said Martínez, who had access to an early report prepared by the town's security forces.

Venezuela's minister of penitentiary services, Iris Varela, confirmed the riot, telling the local newspaper Ultimas Noticias that a group of inmates attacked officers standing guard outside the prison.

The warden was injured by at least one inmate wielding a knife, Varela said.

A once-wealthy oil nation, Venezuela is gripped by a deepening political and economic crisis.

Street violence is common in the nation that has had nearly 5 million residents flee in recent years as public services crumble.

Venezuela has roughly 30 prisons and 500 jails that can holds an estimated 110,000 inmates.

Human rights officials say the prisons are violent and badly overcrowded, with gangs that traffic weapons and drugs in control.

A similar riot occurred a year ago in a nearby jail also in the state of Portuguese, where 29 inmates died at a police jail that housed several hundred detainees. Violence broke out when armed inmates objected to officers entering the jail. (AP)

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