Army helicopters dropped at least three bombs at suspected underground bunkers of Islamic extremists in a north Lebanon refugee camp on Monday, and two more soldiers were killed in the fighting, a senior military official said. The bombs dropped by the helicopters weighed 400 kilograms (880 pounds) each and could level entire buildings, local media said. A military official, speaking on customary condition of anonymity according to army regulations, said one soldier was killed overnight and another died Monday, raising to 140 the total number of troops killed since fighting erupted May 20.