An Iraqi girl stands in front of destroyed houses after a car-bomb explosion, in the Ash Sha'b neighborhood of northern Baghdad Wednesday. A suicide truck bomber struck near the home of an Iraqi police general, killing 18 people and wounding 75 others.

BAGHDAD — A truck packed with rockets blew up Wednesday in a Shiite area of Baghdad, killing 18 people in the deadliest single blast in the city in more than three months. Three U.S. soldiers were killed by gunfire north of the capital.

A U.S. military spokesman said the blast appeared to have been an accident that occurred as Shiite militiamen were transporting the weapons through a densely populated neighborhood of northern Baghdad — possibly to fire at a nearby American base.

Iraqi police said a suicide truck bomber had targeted the house of an Iraqi police general, who was not at home but whose nephew was among those killed. U.S. officials said 75 people were wounded, and police said they included the general's elderly parents.

But the U.S. military disputed the police account, saying Shiite extremists were transporting rockets and mortars on a tractor-trailer when the weapons mistakenly exploded. Witnesses also confirmed the vehicle was carrying weapons.

"They were trying to attack us ... and it went off (accidentally)" said U.S. military spokesman Lt. Col. Steve Stover, who provided the death toll. "They wouldn't waste rockets like that" on a suicide attack.

The force of the blast crumbled several two-story buildings, buried cars under rubble, sheared off a corrugated steel roof and left a large crater on the residential street.

It was the deadliest single explosion in Baghdad since March 3, when a suicide car bomber killed 22 people in eastern Baghdad. Sixteen people died in a mortar attack in the Shiite militia stronghold of Sadr City on April 9.

Wednesday's carnage was a grim reminder of the bombs and killings that rocked the capital before President Bush rushed about 30,000 reinforcements to Iraq last year to curb a wave of Shiite-Sunni slaughter.

More recently, violence has dropped sharply since a May 11 cease-fire ended seven weeks of fighting between U.S. and Iraqi soldiers and Shiite militiamen in the capital's Sadr City district.

Nevertheless, a car bomb exploded Wednesday night in the Shiite district of Karradah in east Baghdad, killing seven people, including three policemen, and wounding 11 other people, according to police and hospital sources who spoke on condition of anonymity because they were not supposed to release the information.

The three American soldiers died when gunmen opened fire on them near the town of Hawija, 150 miles north of Baghdad, a U.S military statement said. No further details were released.

Their deaths brought to at least 4,090 the number of American military personnel who have died in the Iraq war since it began in March 2003, according to an Associated Press count.

Hawija, once a hub for Sunni militants and disaffected allies of Saddam Hussein, was believed to have been pacified in recent months. Last year the town was the scene of one of the largest ceremonies where tribal sheiks joined forces with the Americans to fight al-Qaida in Iraq.

South of Baghdad, Iraqi villagers and soldiers unearthed at least 13 bodies from a shallow, dusty grave in farmland on the outskirts of Latifiyah, a mostly Sunni town that also has some Shiite residents. The bodies were first discovered Tuesday, but digging continued a day later.

Associated Press Television News footage showed Iraqi troops and civilians clawing through dusty soil with shovels. At least three severely decomposed bodies could be seen in side-by-side graves.

The U.S. military said American soldiers, acting on a tip from a local citizen, found at least 10 decomposed bodies Tuesday in the sewer shaft of a building in east Baghdad.

Those victims appeared to have died more than two years ago during the height of the sectarian reprisal killings, the military said.

Latifiyah, about 20 miles south of Baghdad, was taken over by al-Qaida-linked Sunni militants a few years ago. It became a hotbed of Sunni extremist activity before U.S. and Iraqi forces regained control late last year.

Maj. Faisal Ali Hussein, who supervised the digging, said villagers are only now feeling safe enough to point out possible mass grave sites in the area.

Also Wednesday, a car bomb wounded eight civilians in Kirkuk, police Brig. Gen. Sarhat Qadir said. The city is the scene of ongoing ethnic tension among Arabs, Kurds and Turkomen for control of the city, the heart of Iraq's northern oil fields.

Meanwhile, the U.S. military said it detained nine suspects and destroyed two "terrorist safe houses" Wednesday in raids targeting al-Qaida across central and northern parts of the country.

One of the men had been wanted for alleged involvement in distributing weapons and car bombings in Baghdad, the military said in a statement.

Another suspect was responsible for organizing suicide bombings and helping foreign militants enter Iraq, the statement said.

Information from other detainees already in U.S. custody led American troops on Wednesday to two facilities that housed foreign militants west of Mosul, it said. The buildings were safely destroyed.

In a separate operation Wednesday, Iraqi police said they uncovered a large weapons cache near Samarra, 60 miles north of Baghdad.

Among the load were hundreds of explosive belts, three assembled car bombs and several different types of rockets, an officer said on condition of anonymity because he was not authorized to release the information. One suspect also was arrested in the raid.


Associated Press writers Lauren Frayer and Sameer N. Yacoub contributed to this report.