Guwahati: Violence erupted in Assam on Tuesday with 3 people killed and more than 30 wounded in a powerful explosion inside a passenger train, even as tribal militants gunned down two Hindi-speaking migrants, officials said.

A police spokesman said the blast went off inside a carriage of a passenger train at the Diphu railway station, about 300km east of Assam's main city of Guwahati.

The train was bound for Tinsukia in eastern Assam from capital Guwahati.

"The train was waiting at the Diphu railway station when a powerful explosion went off inside one of the crowded coaches," a railway official said by telephone requesting not to be named.

One person died on the spot and two succumbed to their injuries at a local hospital, the police official said.

"There are a large number of women and children among the casualties. The conditions of at least six of them are stated to be critical," the police official said.

"The explosion ripped apart the carriage with people tossed in the air after the blast," Vishal Kumar, a witness who was at the railway station waiting to board another train to Guwahati, said over the telephone.

No militant group has claimed responsibility for the blast. "We are yet to ascertain who could be behind the explosion," the police official said.

In another incident in the same district of Karbi Anglong, militants reportedly belonging to the outlawed Karbi Longri National Liberation Front (KLNLF) shot dead two Hindi-speaking people yesterday.

Indiscriminate firing

A police official said heavily armed KLNLF militants entered village Dolamora, about 290km from Guwahati, and fired indiscriminately on a group of Hindi-speaking people.

"Two persons were killed in the attack and we understand both of them were petty traders," the official said.

The KLNLF is a rebel group fighting for an independent homeland for the majority Karbi tribe in the area.

The KLNLF yesterday launched an economic blockade in the region to pressurise the government to hold peace talks.

"We are looking into the KLNLF's role for the train attack," the police official said.

Assam witnessed a deadly wave of bombings on October 30, in which about 95 people were killed and 300 injured.