Brasilia, May 28 (IANS): The death toll from prison riots in Brazil has increased to 57, as authorities found the bodies of 42 more inmates in four jails.

A fight between inmates during visiting hours led to the deaths of 15 inmates on Sunday at the Anisio Jobim Prison Complex, in the city of Manaus. The inmates were either strangled to death or stabbed with toothbrushes, reports Xinhua news agency.

On Monday,the authorities reported the discovery of more corpses. A total of 42 bodies were found not only at the Anisio Jobim Prison, but also at three other jails in Manaus.

The Prison Administration Secretariat said that the situation was now under control .

So far, there were no reports of warden injuries or inmate escapes.

Riots, killings and mass escapes are common in Brazil's penitentiary system, which international organisations call one of the world's worst and most violent, Efe news reported.

The country has the world's third largest prison population at over 700,000 people, nearly double the they were built to accommodate, according to figures from the Brazilian Forum on Public Safety.