GUWAHATI: A bomb planted on railway tracks in India`s restive northeast ripped through the engine and coach of a passenger train on Thursday, killing one and injuring seven, officials said.

Police blamed the outlawed National Democratic Front of Bodoland (NDFB) for the blast in the early hours of Thursday in Kokrajhar district in the state of Assam.

"The engine and the first coach bore the maximum brunt of the explosion, while another four coaches derailed," S. Hajong, chief spokesperson of the Northeast Frontier Railways, told AFP.

"The casualty figure is low because the train was moving at a very low speed while crossing a rail bridge."

The Assam government sounded a massive security alert on Wednesday evening after police intercepted messages from the NDFB indicating they were planning to target trains, bridges and security forces.

The outlawed group is fighting for a separate nation for the Bodo tribe people. It was blamed for a series of explosions in 2008 which killed about 100 people and injured hundreds more.

At least 10,000 people have died during a two-decade long insurgency in Assam.

BDST: 1043 HRS, July 8, 2010