Updated at 3:25 a.m. (AP) BAGHDAD - A wave of morning bombings killed 18 Iraqis across several cities on Thursday, shattering weeks of calm in a reminder of the nation's continued insurgency. In all, officials said extremists launched nine attacks in Baghdad and in northern Iraq, in Kirkuk, Dibis and Taji. At least 71 people were wounded in the rapid-fire explosions that unfolded over an hour and 15 minutes. There was no immediate claim of responsibility for the attacks, but Baghdad military command spokesman Col. Dhia al-Wakeel said they resembled those carried out by al Qaeda. "They want to send a message that they can target the stability that has been achieved recently," al-Wakeel said. This will not discourage our security forces. The single deadliest bombing came in Dibis, located near the northern city of Kirkuk, 180 miles north of Baghdad. Kirkuk Police Brig. Gen. Sarhad Qadir said a parked car exploded in the Sunni Arab village, killing six passers-by and wounding four. In Baghdad, police said roadside bombs and car explosions targeted security patrols and the nation's top health official, Health Minister Majeed Hamad Amin, as his convoy was driving him to work. But bystanders took the brunt of the attacks that killed eight across the Iraqi capital - mostly in Shiite neighborhoods. Amin, an Iraqi Kurd, was not hurt in the attack on his convoy in the capital's west, but two passers-by were killed and six people were wounded. Police and hospital officials confirmed the Baghdad casualties but spoke on condition of anonymity because they were not authorized to release the information. Additionally, two explosions in Kirkuk targeted a police patrol and the provincial investment official, killing three and wounding 21, Qadir said. And a roadside bomb in the city of Taji, just north of Baghdad, exploded as a security patrol drove by. One bystander was killed and three policemen were among six people who were wounded in the blast. The explosions ended nearly a month of quiet in Iraq, where violence waned since the run-up to the Arab League summit that was held in Baghdad at the end of March. Overall, attacks have dropped sharply nationwide since Iraq threatened to dissolve into civil war five years ago. But bombings and deadly shootings are still common.