Security forces were on maximum alert in Assam on Monday with the outlawed United Liberation Front of Asom (ULFA) observing a protest day to mark its listing as a terror group 16 years ago.
"We have deployed the army, police and paramilitary forces in strength in vulnerable areas as ULFA carries out attacks on this day," said an Assam police official.
The government had on Nov 27, 1990 classified ULFA as a terrorist group and banned it under the Unlawful Activities (Prevention) Act.
Formed in 1979, ULFA is fighting for an independent Assamese homeland and has been blamed for a wave of bombings in the past two months that killed 24 people and wounded 120.
Suspected ULFA rebels launched a grenade attack at a police station in eastern Assam's Nagaon district late Sunday. No one was injured.
"We are particularly worried about attacks by ULFA in crowded places besides oil and gas installations. Security forces have all along been their target although now ULFA does not spare even innocent civilians," the police official said.
Soldiers are engaged in a massive anti-insurgency operation in Assam since Sep 24 after New Delhi called off a six-week ceasefire accusing ULFA of stepping up attacks and extortions.