New Delhi - One person was killed and 50 injured in serial bomb blasts in Agartala, capital of the north-eastern Indian state of Tripura on Wednesday, news reports said.

Four blasts occurred in the space of about 45 minutes in busy areas of the city, including markets and bus stops within a two-kilometre radius, Times Now television reported.

All the blasts were of low intensity, local police official Shreeyash (Eds: one name only) was quoted as saying. He said a fifth bomb had been found and defused.

All the injured had been taken to hospital. Twenty of them were in critical condition, reports said.

A number of secessionist rebel groups are active in north-eastern India. However, recent intelligence reports have suggested that Islamic terror modules of the Harkat-ul-Jehadi-ul-Islami or HUJI based in Bangladesh have been infiltrating into north-eastern India.

Shreeyash said it was too early to pin responsibility for the blasts.

Major Indian cities have been hit by serial bomb blasts in 2008, including Delhi, Jaipur and Gujarat. (dpa)