QUITO: A gunfight between inmates in Ecuador left four dead and 12 injured, authorities said Wednesday, two months after simultaneous riots at four jails claimed 79 lives.

The government's prison authority said 37 inmates are under investigation after the latest outbreak of violence at a facility in Guayaquil -- one of the four jails where gang warfare broke out in February in Ecuador's worst-ever prison violence.

Ecuador's prison system has a capacity to house 29,000 inmates at 60-odd facilities, but a prisoner population of 38,000.

There are 1,500 guards to oversee them -- a shortfall of about 2,500.

In February's violence, inmates were left decapitated and burnt in violence that exposed the power of prison gangs and shocked the South American nation.

In total, 103 inmates were killed in Ecuadorian prisons last year, according to the office of the human rights ombudsman.

Interior Minister Gabriel Martinez said Wednesday that order had been restored at the Guayaquil prison.

He added security has been reinforced at all prisons after the latest "disturbances" in a bid to prevent any escalation.

"We will not allow the violent acts of February in prisons to be repeated," Martinez said on Twitter.