A car bomb exploded outside a police station in the northern Iraqi city of Mosul on Sunday, wounding at least 15 people, police there said, according to dpa. The bomb attack, which targeted the police station in Mosul's city centre, some 400 kilometres north of Baghdad, was the most serious attack in Iraq since US soldiers withdrew from Iraqi cities and towns on June 30. Militants marked that occasion with a truck bombing in the northern Iraqi city of Kirkuk that killed at least 30 people and left at dozens of others wounded. Also in Mosul on Sunday, two militants threw grenades at police patrolling the Corniche neighbourhood of the city. The grenades missed their target, but wounded at least five civilian bystanders, police told the German Press Agency dpa. Mosul, the capital of Iraq's Nineveh province, which is home to one of the most diverse mix of ethnic and religious groups in Iraq, remains the site of deadly, near-daily attacks. In recent weeks, there have been signs of a brewing political confrontation between Kurds and Arabs in the region around the city. Politicians from the Arab nationalist Hadbaa List elected in January's provincial polls took a hard line on Kurdish militiamen in the security forces in the weeks ahead of the scheduled US withdrawal from the city. "I expect that the Kurds will withdraw from the city and there will be a single security force in the city, with not a single Kurd or (Kurdish) Peshmerga (militiaman) in it," Athil al-Najifi, the local governor, told dpa on June 21, a week ahead of the partial US withdrawal. Two weeks prior, Deputy Speaker of Parliament Aref Tayour, from the Kurdish Democratic Party, had proposed dividing Nineveh into two provinces, to reflect the geographic split between areas that voted for the predominantly Kurdish Brotherly List to power in January's polls, and those that voted for the Hadbaa List. Those remarks drew prompt criticism from Sunni members of parliament from the region, as did the Kurdish Regional Government's passage of a new draft constitution for the semi-autonomous Kurdish region of northern Iraq on June 24. The draft, which will go to a regional referendum as part of the July 25 Kurdish parliamentary elections, included predominantly Kurdish parts of Nineveh, and the similarly ethnically divided provinces of Kirkuk and Diyala, in its definition of Kurdistan.