In northern Iraq, at least 33 people have been killed and dozens more hurt in a sucide attack on the police headquarters in Kirkuk. Authorities say two gunmen disguised as police officers drove a car packed with explosives into the building’s entrance. After the blast, gunmen with explosive vests attacked with AK47s and grenades, but guards killed them. It is the third major attack in several weeks in or near the northern city, an ethnically mixed area of Arabs, Kurds and Turkmen at the heart of a dispute over oil and land between Baghdad and the autonomous Kurdistan region. Last month a suicide bomber disguised as a mourner killed at least 26 at a funeral at a Shi’ite mosque in the nearby city of Tuz Khurmato, and days earlier a suicide bomber driving a truck killed 25 in an attack on a political party headquarters in Kirkuk. Several armed groups are active in Kirkuk, and Sunni Islamist insurgents tied to al Qaeda often attack security forces in an attempt to undermine Shi’ite Prime Minister Nuri al-Maliki’s government and stoke sectarian tensions.