Guwahati's Senior Superintendent of Police Nitul Gogoi told PTI there was information that a group of ULFA militants was moving about in the city and police suspected "their hand in the blasts in Fancy market and Pattharquarry areas".

Police recieved a tip-off that three insurgents were holed up in a house inside the forests on Santipur Hill. When police went there in the early hours of Monday, the rebels hurled a grenade at them, he said.

The policemen retaliated, killing one militant on the spot, while two others fled under the cover of darkness. A grenade was found on the dead insurgent and 13 more grenades were found in a carton inside the house.

Gogoi said security in Guwahati had been tightened. Checking of vehicles had been intensified and additional security forces were deployed in vulnerable areas, he said.