Northern Ireland police arrested two men after an abortive bomb attack on a British army barracks. The attack reportedly was carried out by a republican splinter group, the Continuity IRA. Police said the blast at the Shackleton barracks near Londonderry caused no casualties. Authorities later found and defused three more explosives near troop sleeping quarters. "Two men have been arrested and are assisting police with their inquiries into today's explosion," a police spokeswoman said. BBC radio said a representative of the Continuity IRA claimed responsibility for the attack. But police said the caller did not use a recognized code word, leaving them uncertain about the claim's authenticity.