In the deadliest violence since the US formally ended its combat role in Iraq, 37 people were killed on Sunday in Baghdad and Fallujah.
Twin car bombs exploded within moments of each other around 11 a.m. in Baghdad – one near a facility housing federal police, which killed 19 people, the other a few miles away at a busy intersection in the Mansour neighborhood, killing 10, Iraqi authorities said. More than 110 people were injured.
Hours later, a suicide bomber drove into an Iraqi army checkpoint in central Fallujah, a heavily guarded city 40 miles west of Baghdad. Three soldiers and three civilians were killed, and 14 others were injured.
The bombings underscored the dangers still posed by insurgents as American troops cede control over security to Iraqi forces. The US military has drawn down to fewer than 50,000 soldiers who now serve in what officials describe as an advisory role, although they have continued to engage in military operations alongside Iraqi forces.
Although Iraqi military and police now man the country's ubiquitous checkpoints, they remain vulnerable to attack and have failed to win public confidence.
The attack in Fallujah was particularly brazen because Iraqi security forces guard all entrances to the city and bar nonresidents from entering. While no group immediately claimed responsibility, the attack might have been in response to last week's joint US-Iraqi military raid on a suspected insurgent's residence, which left seven people dead.
Insurgents also appear to be exploiting a power vacuum in Iraq as negotiations over forming a new government remain deadlocked six months after national elections.