MANAUS/RIO DE JANEIRO (REUTERS) - Inmates at a prison in Manaus, a Brazilian city deep in the Amazon that has been hit hard by the coronavirus outbreak, briefly took seven prison guards hostage on Saturday (May 2), the local prison authority told Reuters.

The inmates had rioted to create a distraction as others built a tunnel underneath the prison walls, but police snuffed out the scheme after raiding the prison and freed the guards, prison officials said.

There were no reported deaths.

However, 10 prison guards, two police officers and five inmates were lightly injured, the prison authority said in a statement.

Dozens of family members gathered outside the prison walls complained of conditions inside the jail, including insufficient food, cells without electricity, and lack of proper medical attention for inmates.

Some said the spread of the coronavirus throughout the city was making their concerns more urgent.

The rebellion came as the coronavirus outbreak overwhelms public services in Manaus, with authorities burying victims in mass graves and warning residents of an imminent shortage of coffins.

There have been two confirmed coronavirus cases in Amazonas' prisons elsewhere in the state, according to local authorities.

Violence is rife in Brazil's prisons, where organised crime groups often exercise de facto control. Overcrowding is also common and rights groups call conditions medieval, with food scarce and cells so packed that prisoners sometimes have no space to lie down.

In January 2017, almost 150 prisoners were killed as organised crime groups battled each other in several prisons in north and northeastern Brazil. In one particularly violent incident in Manaus, 57 inmates were killed, some of whom were decapitated and thrown over prison walls.

Last year, over 50 inmates were strangled or stabbed to death as rival gangs battled each other in four separate Manaus jails.

Local television stations showed a video earlier in the day, allegedly recorded by an unidentified inmate who complained of sweltering heat and a lack of electricity in the prison.

In a statement earlier on Saturday, the prison authority said the prisoners were demanding the presence of the press and human rights groups.