The second round of violence took place Sunday night. The prisoners were furious that cases were being slapped against many of them for the Saturday violence despite assurances to the contrary.
Late on Sunday, prisoners thrashed an official, Harendra Singh, in barrack 8.
Security reinforcements were rushed to the jail. The prisoners then set fire to barrack 5 in a bid to prevent the police and the Provincial Armed Constabulary from entering the prison.
After extinguishing the fire, officials searched the prison to ensure there were no hidden weapons.
Varanasi District Magistrate Rajmani Yadav said a probe would be conducted into the Saturday and Sunday violence. "No guilty person will be spared," he said. (IANS)