More than 300 pounds of a powerful plastic explosive that had been stolen from a mine was seized in a raid by agents who posed as would-be buyers for the material, authorities said.

Five people were arrested in the raid on a motel Friday night where agents had rented rooms to arrange the bogus purchase, authorities said.There was enough explosive, known as C-3 or Tovex, to blow up a three-block area, said police in this community of 50,000 about 45 miles north of Denver.