Bombs also claimed a toll Monday among civilians in Basra, Iraq's second-largest city and the major metropolis of the Shiite-dominated south, which has witnessed less violence than Sunni areas. A large car bomb exploded along a bustling street packed with shops and restaurants as people were enjoying an evening out after the daily Ramadan fast. At least 20 were killed and about 40 wounded, police Lt. Col. Karim al-Zaidi said.
Watch raw video of the response after the attacks
Military commanders have warned that Sunni insurgents will step up their attacks in the run-up to the Dec. 15 election, when Iraqis will choose their first full-term parliament since the collapse of Saddam Hussein's regime in 2003.
To guard against such attacks, the military has raised the number of American troops in Iraq to 157,000 — among the highest levels of the Iraq conflict.
Most of the combat deaths and injuries in recent months have been a result of the increasing use by insurgents of sophisticated homemade bombs, responsible for the deaths of the seven Americans killed since Sunday. The military refers to those bombs as "improvised explosive devices," or IEDs.
Last Friday, an IED killed Col. William W. Wood, 44, of Panama City, Fla., an infantry battalion commander. He was promoted posthumously, making him the highest-ranking soldier killed in action in the Iraq conflict, according to the Pentagon.
"We see an adversary that continues to develop some sophistication on very deadly and increasingly precise stand-off type weapons — IEDs, in particular," Pentagon spokesman Lawrence Di Rita told reporters Monday.
In other developments: