A banned militant group in Pakistan blamed a deadly suicide bombing at one of its mosques in the Khyber Agency on a rival group. Lashkar-e-Islam said the bomber struck during Friday services at the Dars Mosque in the Tirah Valley, The Nation reported. The group said the bomber was gunned down when he refused an order to stop but the impact of the bullets set off his suicide vest. The number of casualties was in dispute. Lashkar-e-Islam said 11 of its members and two passersby were killed in addition to the bomber, while authorities said five deaths had been confirmed and seven people were injured. The Tariq Group, a section of the Taliban, took responsibility for the bombing in a telephone call and claimed 25 Lashkar-e-Islam members had died. The bombing damaged the mosque\'s madrassa or school. The Taliban and Lashkar-e-Islam have been struggling for influence in the tribal areas, including the Khyber Agency, which runs along the Afghan frontier. Lashkar-e-Islam was the target of two recent attacks -- one three weeks ago, when 22 people were killed at another Tirah Valley mosque, and another in February, when dozens died in February at a mosque in the Kurram Agency.