IMPHAL: A grenade was hurled by militants at the residence of a Manipur government official in Imphal West district on Friday but it failed to explode, police sources said. The residence of head clerk-cum cashier of Oriental College of Oinam Ratna at Tera area, about 7 km from here was targetted by the militants who escaped. The sources said that extortion could have been the motive for the attack. The grenade was later defused.(PTI)