"Killing of innocent people in Sonitpur and Kokrajhar is an act of cowardice. Our thoughts and prayers are with the families of the deceased," tweeted Prime Minister Modi.
"I spoke to Assam CM Shri Tarun Gogoi and Home Minister Rajnath ji. Rajnath ji will travel to Assam and take stock of the situation," he added.
33 people were killed on Tuesday evening in attacks by NDFB in Kokrajhar and Sonitpur districts of Assam, following which indefinite curfew has been imposed in five police station areas of Sonitpur district.
Union Home Minister Rajnath Singh will pay visit to the state later today, in order to take stock of the situation.
According to reports, the State Home department has instructed the administration of all the districts to remain alert.
The world heritage site, Manas National Park has also been closed for three days in a bid to intensify operation against militants.