Two people were killed and several more injured in a grenade attack by suspected ULFA(I) militants in Sibsagar district of upper Assam on Thursday evening, police said.

The grenade exploded at a hardware shop in the Demow Chariali area of the district, killing a customer, Anup Gupta, and the shop owner, Kamal Agarwal, they said.

Several bystanders also suffered minor injuries.

The ULFA(Independent) had allegedly served an extortion notice on the shop owner a few days ago, police said, adding that the militants had also hurled a grenade at his shop about three years ago.

The ULFA(I) has stepped up its activities in upper Assam districts, and during the recent past, there has been a spurt of killings and kidnappings attributed to the outfit, including the killing of five people at Dhola in Tinsukia district.

Chief Minister Sarbananda Sonowal condemned the incident and said the culprits would be brought to book.

Sonowal, who is currently in New Delhi, directed Director General of Police Kuladhar Saikia to take immediate measures to nab those involved in the incident.

He termed the attack an "act of cowardice" and expressed his deepest sympathy to the bereaved families, an official release said.

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