Guwahati: Four powerful grenade explosions -- three in Dibrugarh and one in Charaideo districts -- rocked Assam on Sunday morning as the country celebrated Republic Day, police said. In Dibrugarh district, an explosion took place at Graham Bazar and another beside a gurudwara on A T Road, both under Dibrugarh police station.

Another explosion rocked the oil town of Duliajan whose details are still awaited, police said. Another explosion rocked Teok Ghat under Sonari police station of Charaideo district, they said.

Senior officials have rushed to the explosion sites and details of a casualty are awaited, police added.