During rush hour Tuesday, a car bomb killed 11 people and wounded an additional 36 in Istanbul, near the mayor’s office and a major university. The device was detonated while police buses were passing through the area, said Istanbul Governor Vasip Sahin. Seven police officials and four civilians were killed in the attack. State-run media reported that gunshots were also heard after the blast. The incident marks the fourth significant bombing in Istanbul this year. Kurdish militants have carried out similar attacks in the city, including one last month. No one has claimed responsibility for the attack.