Suspected United Liberation Front of Asom militants on Sunday set off three bombs injuring five policemen and destroying a power transmission in tower in Assam on Sunday.

The militants lobbed a hand grenade at a police party near the Commerce College area of Guwahati in the busy evening hours, Senior Superintendent of Police J Gogoi said.

In another blast triggered at the Panbazaar police reserve, one policeman was injured.

Gogoi said a massive manhunt has been launched and security tightened in the city.

Earlier in the day, ULFA militants blew up a power transmission tower of power grid in Sonari in upper Assam.

There was however no casualty. Following the explosion, power supply to nearby township including Sonari have been disrupted.

The ultras detonated two bombs in crude oil and gas pipelines in the Sibsagar district on Saturday.