"We confirm that there are 23 dead detainees and 14 wounded police," official said (Representational)

At least 23 inmates were killed and 14 police wounded in clashes at a jail in western Venezuela on Friday, an NGO that defends prisoner rights said.

The clashes broke out when special forces (FAES) police attempted to rescue some visitors who had been taken hostage Thursday by inmates at the police station jail in Acarigua.

"This morning (authorities) sent the FAES and there was a clash. The detainees had weapons, they shot at the police. Apparently they also exploded two grenades," Carlos Nieto, director of the Una Ventana a la Libertad NGO, told news agency AFP.

An internal police report, quoted by the NGO, said several officers were wounded by shrapnel.

"We can confirm that there are 23 dead detainees and 14 wounded police," said Nieto.

The prisons ministry didn't comment on the incident, saying police station jails aren't under its control.

Violence is a problem in such detention facilities, where inmates are supposed to be held for a maximum of 48 hours, Una Ventana de la Libertad said.

There are around 500 of them in the country, holding 55,000 people even though their total capacity is just 8,000, the NGO added.

Venezuela has one of the worst records for prison violence in the region.

In March 2018, 68 inmates died in a fire at a police jail in the northern city of Valencia.

And in August 2017, a riot at a facility in the southern Amazonas state left 37 prisoners dead.