At least seven people were critically wounded on Saturday in a powerful grenade explosion at a market in Assam, the latest in a wave of bombings linked to next week's Independence Day, officials said.
A police spokesman said militants, suspected to be from the outlawed United Liberation Front of Asom (ULFA), tossed a grenade at a roadside vegetable market at Bamunimaidam in the heart of Guwahati.
"Seven civilians, most of them either shoppers or vendors, were seriously injured in the attack," said a police official A Bora.
Witnesses said the militants hurled the grenade and sped away in a motorcycle. The injured were taken to a local hospital. They suffered multiple wounds.
The Assam government on Saturday sounded a high security alert deploying army, police and paramilitary soldiers to thwart separatist attacks.
ULFA rebels on Friday night killed six police commandos in a powerful landmine explosion in the eastern Tinsukia district, 550 kms from Guwahati.
Five rebel groups from the northeast have called a general strike to boycott the Independence Day.
Militants in the northeast have been boycotting Independence Day and Republic Day celebrations for years to protest New Delhi's rule over the vast region rich in oil, tea and timber.
The run-up to the events has always been violent, with rebels striking vital installations including crude oil pipelines, trains and road and rail bridges, besides targeting soldiers.