Picture: @oveprisiones/Twitter

Bogota - At least 23 detainees have been killed in a mutiny in police cells in western Venezuela, the NGO Venezuelan Observatory of Prisons tweeted on Friday.

The mutiny occurred in Acarigua in Portuguesa state, according to the prisoners' rights advocacy group.

Fourteen prison officials were injured in the incident at a police coordination centre on Friday morning, daily El Nacional reported.

There was a shoot-out and grenade explosions, journalist Daniel Colina tweeted.

A video posted on social media shows a masked, gun-wielding inmate with two female visitors to the cells. He says he is "ready to die," while one of the women calls for "dialogue."

Injured victims were believed to have been taken to a local hospital, where a heavy presence of security forces was observed, according to broadcaster NTN24.