BAGHDAD, Iraq - A string of bombings killed at least 15 people Monday in the Baghdad area, a day after a massive car bomb attack in a Shiite area market delivered the first major blow to the U.S.-led security crackdown. Attacks in other parts of Iraq pushed the overall death toll near 30.
U.S. forces also reportedly came under attack. They clashed with insurgents north of Baghdad after a suicide bomber apparently tried to break through barriers around a joint U.S.-Iraqi base, area residents told The Associated Press. U.S. military officials said they were looking into the incident.
In Baghdad, five people were killed when a suicide attacker detonated a bomb-rigged belt on a public bus headed for the mostly Shiite area of Karradah in central Baghdad, police reported.
A roadside bomb killed three policemen in the Shiite area of Zafraniyah in southeastern Baghdad, officials said. Only 100 yards away, a bomb hidden in an open-air market exploded, killing at least five.
In Mahmoudiya, 20 miles south of the capital, a car bomb went off among auto repair shops, killing two and wounding two, police said. Mahmoudiya is mostly Shiite with Sunnis living in villages around the community and has long been a flashpoint for sectarian violence.
Elsewhere in Iraq, a car bomb in Ramadi, about 90 miles west of Baghdad, killed at least nine bystanders congregated at a police checkpoint in the aftermath of a failed suicide attack.
And in Duluiyah, a Sunni area about 45 miles north of Baghdad, at least four were killed when a bomb-rigged car exploded.
Meanwhile, the U.S. military announced Monday that a U.S. Marine was killed two days earlier during combat operations in Anbar province, a Sunni insurgent hotspot west of the capital.
The latest attacks were a sobering reminder of the huge challenges confronting any effort to rattle the well-armed and well-hidden insurgents.
On Sunday, police said at least 62 people died in the attack in the mostly Shiite area of New Baghdad. Nearly 130 people were injured.
Another person was killed in a car bombing Sunday in the Shiite militia stronghold of Sadr City.
Just a few hours before the weekend blasts, Lt. Gen. Abboud Qanbar led reporters on a tour of the neighborhood near the marketplace and promised to "chase the terrorists out of Baghdad." On Saturday, the Iraqi spokesman for the plan, Brig. Gen. Qassim Moussawi, said violence had plummeted 80 percent in the capital.
Prime Minister Nouri al-Maliki condemned the bombing as a desperate act by "terrorists" and "criminals" who sense they are being squeezed.
"These crimes confirm the defeat of these perpetrators and their failure in confronting our armed forces, which are determined to cleanse the dens of terrorism," al-Maliki said in a statement.
U.S. Ambassador Zalmay Khalilzad said the bombings underscore the "increasing desperation felt by criminals" and would only serve to "galvanize Iraqi forces and their coalition partners."
Sunday was by far the deadliest day since the security sweeps began last week. On Thursday, a string of car bombs killed seven civilians on the first full day of the house-to-house searches for weapons and suspected militants.
The U.S.-led teams have faced limited direct defiance as they set up checkpoints and comb neighborhoods. But that could change as they move into more volatile sections. The next could be Sadr City, a stronghold of the Mahdi Army militia loyal to radical Shiite cleric Muqtada al-Sadr.
U.S. soldiers pressed closer to Sadr City and the reception changed noticeably. In previous days, Shiite families opened their doors to welcome the troops - feeling that the American presence would be a buffer against feared attacks from Sunni militia.
On Sunday, in areas closer to Sadr City, parents slapped away the candy and lollipops given by American soldiers.
"The Baghdad security plan is very important to push Iraq ahead," said Haider al-Obeidi, a parliament member from the Dawa party of the prime minister al-Maliki.
Meanwhile, borders with Iran and Syria - shut for three days as the plan got under way - reopened Sunday. But new and strict rules will apply.
Moussawi was quoted in the Azzaman newspaper as saying the crossing points to the two nations would be open for only several hours a day and under "intense observation."
The United States and allies claim Iraqi militants receive aid and supplies from Iran, including parts for lethal roadside bombs targeting U.S. forces. Iran denies any role in trafficking weapons.
In Buhriz, a Sunni-dominated town about 35 miles north of Baghdad, U.S. and Iraqi soldiers kicked in doors and scoured homes, but most dwellings were eerily empty.
Soldiers confiscated new Iraqi army uniforms in a building not known to house troops, along with a rocket-propelled grenade launcher and AK-47 magazines. There has been growing suspicion that militants have posed as Iraqi soldiers in some attacks and ambushes.
In another house, medical supplies were scattered about - saline bottles, IV bags, syringes - in what soldiers believe was a makeshift aid station for insurgents.