A bomb tied to a bicycle exploded outside a supermarket in eastern India on Wednesday, killing at least two people and wounding 16 others, police said.

Kundan Lal Tamta, an inspector general of police, said the bomb went off in Alipurduar, about 400 miles northeast of Calcutta, the capital of West Bengal state.

All of the injured were hospitalized, including three in critical condition, Tamta said.

There was no immediate claim of responsibility.

"We can't say right now which group is involved in the attack," Tamta told The Associated Press.

The Kamatapur Liberation Organization, a regional rebel group, has been fighting since 2000 for a separate state comprising parts of the neighboring states of West Bengal and Assam.

The area also is near India's troubled northeast, which is beset by dozens of conflicts and an array of rebel groups. More than 10,000 people have died in separatist violence over the past decade.