A suicide bomber struck a crowded restaurant in northern Iraq on Thursday where Kurdish officials were meeting with Arab tribal leaders to discuss long-standing ethnic tensions, killing at least 55 people, police said. It appeared to be the deadliest attack in Iraq in nearly six months. Kirkuk, the center of Iraq's northern oil fields, has seen fewer attacks than other regions such as Baghdad but remains the focus of years of competition and political wrangling among ethnic groups with rival claims to the city. Police Brig. Gen. Sarhad Qadir, who gave the casualty figures, said the blast occurred in the Abdullah Restaurant just north of the contested oil city. He said 120 people were wounded and that the dead included five women and three children. A Kurdish official said Arab tribal leaders were having lunch with members of the Patriotic Union of Kurdistan, the party of President Jalal Talabani.