A police spokesman said on Tuesday the explosion went off as the train was stopped at a railway station about 300km east of Assam's main city of Guwahati.

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

"There are a large number of women and children among the casualties," the spokesman said.

No one has claimed responsibility yet for the attack.

Separatist rebels are often blamed for attacks in Assam state, a region wracked by violence over the past few decades.

But co-ordinated bomb blasts in Assam in October, which killed at least 77 people, were blamed on attackers from neighbouring Bangladesh in league with separatists.

Source: Agencies