A Sunni insurgent coalition led by al-Qaida in Iraq claimed responsibility on Tuesday for a suicide bombing that hit a US-promoted reconciliation meeting of Shiite and Sunni tribal sheiks, killing 15 people. The claim came in a posting on an Islamic militant Web forum, signed by the Islamic State of Iraq, the umbrella group set up by al-Qaida's branch in the country. The group said it "has promised the government of apostates painful blows, and here it has fulfilled its promise."