GUWAHATI: At least three people including a regional leader of India's ruling Congress were hurt Monday when a grenade exploded at local party headquarters in the northeastern city of Guwahati.

Unidentified attackers hurled the hand grenade inside the office of the regional chapter of India's ruling party, witnesses said. The building was packed with supporters at the time.

Among those injured were Congress general secretary Ranjan Bora and the party's local spokesman Mehdi Alam Bora.

A Congress government administers Assam, of which Guwahati is the largest city. No one has claimed responsibility for the attack, police said.

Some 30-odd militant groups are active in the tea- and oil-rich state, where some outfits are battling for independent homelands for ethnic Assamese.