By Subir Bhaumik
BBC News, Calcutta
Separatist rebels have attacked a train in India's north-eastern state of Assam, killing at least one policeman, police say.
At least 15 other people were injured in the attack by suspected members of the Dimasa tribe.
Police said the rebels fired indiscriminately on the Barak Valley Express train as it approached Wadrendisa station in North Cachar.
The Dimasa are one of a number of separatist groups fighting in Assam.
The dead officer was from the Central Reserve Police Force.
One of the injured officers is in a critical condition, doctors at the Maibang rural hospital said.
Assam police chief GM Srivastava said rebels of the Black Widow faction were involved in the attack.
The faction is headed by Jewel Garlossa and is fighting for an independent homeland for Dimasa tribes in Assam's central hill region which connects the state's Brahmaputra and Barak valleys.
Last year, the rebels set fire to several railway stations and attacked railway employees in North Cachar, forcing the railway authorities to halt train services for a number of days before they were resumed with heavy security.
Jewel Garlossa was part of the main Dimasa rebel group, the Dima Halam Gaogah, which started negotiations with the Indian government five years ago.
He decided to continue the armed struggle.