By Subir Bhaumik
BBC News, Calcutta
The blast comes as India prepares for its general election
Eight people have been killed and dozens hurt in explosions in four towns and cities in India's north-eastern state of Assam.
Seven people died when a bomb exploded outside a restaurant in Guwahati and another in a bomb attack on a market in the town of Dhekiajuli.
Grenade attacks in Mankachar and Udalguri caused a number of injuries.
Police told the BBC the separatist United Liberation Front of Assam (Ulfa) was responsible for the explosions.
Assam police chief GM Srivastava told the BBC two people were killed at the scene in Guwahati's Maligaon district and five more died of their wounds in hospital.
Many vehicles were destroyed by the explosion close to the local headquarters of Indian railways.
Many bystanders helped the injured although angry mobs also pelted police and public transport with stones after the explosion.
Correspondents said blood and body parts were strewn over the entrance to the restaurant.
In a second attack, a bomb exploded in a market in the town of Dhekiajuli. One person died and eight were hurt, two seriously.
In the third attack, two people were wounded by a grenade in Mankachar in the western district of Dhubri.
Six people were hurt in another blast at a market in Udalguri in central Assam.
Last week more than 10 people were injured when a bomb exploded not far from where India's External Affairs Minister Pranab Mukherjee was to address a rally.
Mr Srivastava said: "[The Ulfa] set off bombs before their "Raising Day" every year and this year is no different. We have information of some Ulfa strike squads entering Assam in the past 15 days and we are trying to pin them down."
The Ulfa was raised, or founded, on 7 April 1979 to fight for Assam's independence.
Intelligence officials say Ulfa is also flexing its muscles before the forthcoming Indian parliamentary elections.
Prime Minister Manmohan Singh is scheduled to visit Assam on Tuesday to campaign for his Congress party.
Assam Chief Minister Tarun Gogoi said: "The Ulfa is killing the innocent people of Assam. They will be punished by our people."
He said Ulfa was trying to disrupt the elections.
The organisation has been relatively quiet in recent months after being suspected of carrying out massive serial explosions in October last year, in which 87 people died.