Three men planting explosives near a British military barracks today fired at a guard before fleeing their bungled bombing attempt, officials said. Investigators later found 65 pounds of the high-powered explosive Semtex in three satchels outside a housing block at the British army's Langenhagen Barracks in Hanover, British military officials said. It was not known who was responsible. A Ministry of Defense spokesman in London said: ``We cannot say the men were IRA at this moment in time. All we can say is that they were terrorists.'' The Irish Republican Army has been blamed for numerous attacks against British military installations in West Germany over the past few years. The IRA has waged a campaign to drive the British from Northern Ireland and unite the Protestant-dominated province with the overwhelming Roman Catholic Irish Republic. According to police, a civilian guard making the rounds with a security dog noticed three suspicious people on the barracks grounds about 2 a.m. Three shots were fired by the people, said a British military spokesman, who spoke on condition of anonymity. He said the guard was not injured. Col. Henry Day, Chief of Public Information for the British Forces in Germany, said the attackers had cut a hole in the barracks' perimeter fence. He told British Broadcasting Corp. radio that 70 soldiers were moved from the building. ``It was Semtex, with a wire timing device,'' Day said. He said one satchel contained 10 blocks of explosives, and the second nine blocks. He said he had no details on the third.