Destroyed vehicles are seen at the site of a car bomb that was set off by a suicide attacker in the center of Baghdad. (KHALIL AL-MURSHIDI/AFP/GETTY IMAGES)

At least 49 people were killed in eight cities across Iraq on Tuesday in a string of bombings and shootings that shattered tightened security ahead of a much-anticipated meeting of the Arab League here next week.

Dozens of explosions marked the attacks, which bore the hallmarks of operations by the Iraqi offshoot of al-Qaeda, nine years to the day after the U.S.-led invasion of the country.

Two blasts rocked central Baghdad, where city officials said five people were killed near a major bus station and a car bombing killed three others outside the Foreign Ministry, the center of planning for the summit. Outside a church in the Mansour neighborhood, three guards were fatally shot.

Ten people were killed in the Shiite holy city of Karbala, a traditional pilgrimage site, while attacks in Diyala and Anbar provinces and the central city of Hilla left at least nine dead, including two members of the security forces who were fatally shot at checkpoints in Diyala.

In the ethnically mixed northern city of Kirkuk, 13 police officers were killed when a car bomb detonated outside a police station, and a civilian died in another attack. Five people were killed in the northern city of Tikrit.

The violence followed the killing of more than 20 police officers in Anbar this month and an attack on police cadets in February. The wave of attacks is worrying Iraqi and Western officials.

“I would classify what we are seeing as a resurgent al-Qaeda,” one U.S. official said in an interview this month. The organization is “tremendously resilient, and I don’t see their ideology going away anytime soon,” he said, speaking on the condition of anonymity to discuss the sensitive issue.

“You have to put pressure on al-Qaeda by decapitating them over and over again,” he added.

When U.S. troops withdrew in December, they left behind Iraqi security forces that had improved but still lacked vital intelligence-gathering capacity and the forensic training needed to investigate and prevent attacks.

Iraqi officials said that the Arab League summit set for next week would go ahead as planned but that as a security measure, beginning Sunday, no government employees would work until April 1.

Prime Minister Nouri al-Maliki and his officials have gone to great lengths to encourage Arab leaders to attend the meeting, seeing it as symbolic of Iraq’s return to sovereignty and normalcy in the wake of the American withdrawal.

But observers say terrorist groups are likely to increase their activity as the meeting approaches. Parliament speaker Osama al-Nujaifi told reporters last month that a similar wave of bombings appeared designed “to spark sectarian strife among the Iraqi people and to prevent the Arab League meeting from being held.”

Military commanders say they have called in forces from across Iraq to secure the capital ahead of the summit, have plans to halt air traffic for days beforehand and might shut down parts of Baghdad.

But Maj. Gen. Hassan al-Baydhani of Baghdad’s military command told the Associated Press last week that he anticipated attacks before the summit.

“Our war with terrorism is still ongoing,” he said. “Our enemy is not easy.”