By Subir Bhaumik BBC correspondent in Calcutta

Seven people have been killed in fresh clashes in the Indian state of West Bengal.

Four of the victims, said to be Congress supporters, died in attacks by Marxists at the town of Chopra.

On Wednesday, Congress supporters murdered a Marxist district committee leader, Akbar Ali, by hanging him in the town.

Three Marxist supporters were also killed when police opened fire to prevent a mob from attacking some Congress activists.

The Congress supporters were being held at a police station for alleged involvement in the killing of the Marxist leader.

Killings

Police say Marxist supporters were attacking the houses of Congress supporters as well as party offices around the town of Chopra in retaliation for the murder of Akbar Ali on Wednesday.

Congress leader, Abdul Haque, was killed by rebels at Dangipara village near Chopra on Thursday and three other Congress workers were killed in the same area on Friday.

Marxist supporters burnt down the houses of ten Congress activists and two local party offices.

Officials in Calcutta say additional police and paramilitary personnel have been deployed to control the situation.

But they say the situation remains volatile two days after a mob of Congress supporters lynched Mr Ali in front of their party office.

The three Marxist supporters who were killed died in subsequent attacks when police opened fire as they attacked Congress activists at the police station in Chopra.

West Bengal is due to hold elections for more than 50,000 village council - or panchayat - seats on 11 May.