All the victims in the attack by ULFA-I terrorists were Bengalis, the police said.New Delhi/ GUWAHATI: At least five people were killed by suspected United Liberation Front of Assam or ULFA terrorists in upper Assam's Tinsukia district on Thursday evening.Initial reports said the terrorists belonged to the the ULFA-Independent faction led by Paresh Baruah.

The terrorists wore battle fatigues and randomly picked five people at gunpoint from Kherbari Bisonibari area and killed them by the bank of the Lohit river, reports said.

All the victims were Bengalis, the police said.The Army has launched a massive counter-insurgency operation along the Assam-Arunachal Pradesh border.

The Assam Rifles is keeping a vigil on the porous Indo-Myanmar border.Several Bengali organisations have called for a 12-hour bandh in Tinsukia district today to protests the killings.

West Bengal Chief Minister Mamata Banerjee has also said the Trinamool Congress will take out rallies across the state.

Congress has demanded a CBI probe into the killing.

The party also said it will join the protests called by Trinamool Congress.

Union Home Minister Rajnath Singh also condemned the attack on Twitter.

"Deeply anguished by civilian casualties in an attack in Upper Assam region.

It is a reprehensible act of mindless violence.

Spoke to Assam CM Shri @sarbanandsonwal regarding the incident and asked him to take strict possible action against the perpetrators of this heinous crime," he said.Police have summoned pro-talk ULFA leader Mrinal Hazarika.

He had recently made a provocative speech on the presence of Bengali organisations in the state.

His comments had led to wide scale protest.It is not immediately known if the police has summoned Mr Hazarika in this context.

He is being interrogated at the Panbazar Police Station but the chances of his arrest cannot be ruled out.

The Army has launched a massive counter-insurgency operation along the Assam-Arunachal Pradesh border.

The Assam Rifles is keeping a vigil on the porous Indo-Myanmar border.All Assam Bengali Youth Students Federation has called a 12-hour shutdown in Tinsukia.All the victims are from Bengal, the police said.

The victims have been identified as Shyamlal Biswas, Ananta Biswas, Abhinash Biswas, Subal Biswas and Dhananjay Namashudra, the police said.

ULFA has denied role in the attack.

According to reports, the attack was carried by Paresh Baruah faction of the terrorist group.

Trinamool Congress said it will hold protest rallies in Kolkata, Siliguri, Alipurduar, Jalpaiguri, Nadia and other places.

Assam police chief Kuladhar Saikia and top officers rushed to the spot about 500 km from state capital Guwahati.

The terrorists were in battle fatigues and randomly picked five people at gunpoint from Kherbari Bisonibari area and killed them by the bank of the Lohit river.

All the victims were from Bengal.

At least five people were killed by United Liberation Front of Assam or ULFA faction led by Paresh Baruah.