New Delhi  - Indian security forces entered Lalgarh town in the eastern state of West Bengal Saturday in an attempt to reclaim the area from Maoist-backed tribes, news agency reports said.

The paramilitary fighters and state police reached Lalgarh police station without any casualties or incidents, NDTV television channel and PTI news agency reported.

Lalgarh and its surrounding villages, about 200 kilometres west of state capital Kolkata, had been declared a "liberated zone" by the tribal people and Maoists who had pushed out state police and administrators and gone on a rampage killing members of the governing communist party in West Bengal.

Given the Maoist strategies of mining roads and using local people, specially women and children, as human shields, the forces advanced cautiously as the operation entered its third day, the reports said.

The Maoists blew up a bridge and set off a landmine earlier in a bid to stop the security forces.

The forces also came under intermittent fire from Maoists at the Pingboni-Sarenga road and two landmines on the road blocked with trees were defused, senior police official Humayan Kabir said.

The Indian government on Friday asked the Maoist guerrillas in the area to lay down their arms and enter talks as troops closed in on the area.

At least 10 activists from the ruling Communist Party of India-Marxist (CPI-M) were killed in violence in the region and police stations and party offices were burnt down since June 14.

Maoist guerrillas, who operate in 13 Indian states, say they are fighting for the rights of the landless, poor and tribal people.

According to unofficial estimates, more than 3,000 people, including rebels, have been killed in Maoist violence since January 2005.

Prime Minister Manmohan Singh has described the Maoist insurgency as one of the gravest internal security threats facing India. (dpa)