Officials in Honduras say inmates have taken control of a prison in the city of San Pedro Sula.
At least one person was killed and 10 injured when prisoners opened fire on each other on Wednesday.
The prison governor said guards had surrounded the jail but he had ordered them not to go in to “avoid a bloodbath”.
Honduran prisons are notorious for overcrowding, rioting and violence; 13 inmates died in the same jail in March.
Officials said a fight broke out on Wednesday in the block housing inmates not aligned with gangs.
Prison Governor Orlando Leiva said the motive could have been a fight about a woman.
“We have not yet been able to confirm that report because the women who were in the prison are still being held by the prisoners,” Mr Leiva said.
Violent and overcrowded
The governor said that when the shooting started, the guards followed security protocols, opening the cell doors and securing the prison’s perimeter.
Thirty patrols are stationed around the jail to prevent convicts from escaping.
The Bishop of San Pedro Sula, Romulo Emiliani, is negotiating with the inmates in an attempt to reach a peaceful outcome to the stand-off.
Honduras, which has the world’s highest murder rate and a huge gang problem, struggles to house its inmates.
The country’s 24 jails, built for some 8,000 inmates, are currently holding more than 12,000.
In February, a fire in a jail in Comayagua, north of the capital Tegucigalpa, killed 361 people.