BAGHDAD (AP) — Bombings and shootings ripped across Iraq on Monday, killing at least 106 people in the deadliest day in more than two years. The coordinated attacks in 15 cities sent a chilling warning that al-Qaida is slowly resurging in the security vacuum created by a weak government in Baghdad and the departure of the U.S. military seven months ago.

Though there was no immediate claim of responsibility, the leader of al-Qaida in Iraq declared last week a new offensive aimed at sowing instability across the country.

Iraqi militants have kept up a steady drumbeat of deadly attacks since the U.S. pulled out in December, ending nearly a decade of war. They have sought to increase the chaos created by the deepening sectarian political crisis that pits Sunni and Kurdish leaders against Shiite political powers.

“Al-Qaida is trying to send a message that it is still strong and can choose the time and places to attack,” said Shiite lawmaker Hakim al-Zamili, a member of parliament’s security and defense committee. He said weaknesses in Iraq’s ability to gather intelligence about terror plots, or stop them despite security checkpoints has shown how toothless the government is in protecting its people.

Al-Zamili also raised the specter of al-Qaida infiltrating security forces. If these gaps are not closed quickly, he said, “the attacks and explosions will continue and al-Qaida will be stronger.”

In one brazen assault on Monday, three carloads of gunmen pulled up at an Iraqi army base early Monday near the northeastern town of Udaim and opened fire, killing 13 soldiers before escaping, two senior police officials said.

The deadliest attack, however, took place just north of Baghdad in the town of Taji, where a double bombing killed at least 41 people. The blasts were timed to hit as police rushed to help victims from a series of five explosions minutes earlier.

Monday’s violence bore most of the hallmarks of al-Qaida: the bombings and shootings all took place within a few hours of each other and struck mostly at security forces and government offices — favorite targets of the predominantly Sunni militants. And most of it happened in the capital and in northern areas the terror group used to control and where they now stand the best chance of regaining a foothold.