Inmates of Hooghly jail attacked policemen with bricks and sticks and set fire to a portion of the prison premises to protest the transfer of a criminal wanted in several cases of murder and extortion to Dum Dum Central jail in Calcutta on Monday.

Senior administrative and police officers - including the district magistrate, the superintendent of police, the sub-divisional police officer and the sub-divisional officer - rushed to the spot and a huge contingent of cops from four police stations were deployed outside the jail along with Rapid Action Force personnel before the inmates returned to their cells.

Three hundred-odd inmates ran amok for more than two hours, damaging jail offices, smashing flowerpots and setting fire to the jail kitchen and a wooden door at the main entrance. Three fire tenders were called to douse the flames.

The trouble began around 6pm when a group of inmates returned to the jail after being produced in a Chinsurah court. Nepu Giri, who had been arrested last week with 40kg of ganja, had been part of the group but was not among those who returned.

"When inmates found out that Giri had been transferred to Dum Dum jail, they attacked the policemen with broken pieces of bricks. The cops ran for cover but more inmates joined in," said an officer of Chinsurah police station.

Giri is a prime suspect in the murder of notorious criminal Hubba Shyamal and is himself wanted for murder.

A 500-strong contingent of policemen reached the prison around 8.30pm and surrounded it from all sides. Announcements were made on a loudhailer, asking the inmates to surrender.

Realising that they had been outnumbered, a prisoner announced on a microphone in the jailer's room that the inmates were returning to their cells and locking themselves in.

The policemen entered the jail five minutes later to find at least two policemen and two jail employees lying injured. The condition of one of them - Sukumar Mukherjee, a cook - was stated to be serious. He was admitted to hospital.