Both up and down Santiniketan Express and down Rampurhat-Howrah Viswabharati Fast Passenger were cancelled due to the obstructions.

Twelve express trains were also detained at various stations for some time as the agitators squatted on railway tracks, the statement added.

The state government had launched a massive security operation by deploying central paramilitary troopers and state armed policemen to flush out Maoist extremists from West Midnapore's Lalgarh region last month after the ultras virtually established a free zone there.

But after more than five weeks of action, the security forces have failed to nab any top Maoist leaders, while the ultras killed several activists of the state's ruling Communist Party of India-Marxist (CPI-M) and also abducted and later released a police officer.

The Maoists have been active in areas under 21 police stations of the state's three western districts - West Midnapore, Bankura and Purulia.