Baghdad, Iraq ? Insurgents staged a bold daylight assault Monday against a U.S. combat post north of the capital – first striking with a suicide car bombing, then firing on soldiers pinned down in a former Iraqi police station. At least two soldiers were killed and 17 wounded, the military said.

Elsewhere, three U.S. soldiers were killed and two were wounded Monday in a roadside bombing southwest of Baghdad, the U.S. military said. The military also announced the deaths of three Marines and one soldier since Saturday while conducting combat operations in the western province of Anbar.

Altogether, nine U.S. service members have been reported killed since the beginning of the weekend, six of them Monday.

The head-on attack north of Baghdad was notable for both its tactics and target. Sunni insurgents mostly have used hit-and-run ambushes, roadside bombs or mortars on U.S. troops and stayed away from direct assaults on fortified military compounds to avoid U.S. firepower.

It also appeared to fit a pattern emerging among the suspected Sunni militants: trying to hit U.S. forces harder outside the capital rather than confront them on the streets during a massive American-led security operation.

But the sweeps have done little so far to ease the city’s pain.

Nearly 100 people have died in two days of blasts and sectarian bloodshed in and around Baghdad – most in areas dominated by the majority Shiite Muslims – and Iraqi officials who predicted swift results for the security operation have gone suddenly silent.

“A coordinated attack” is how the U.S. military statement described the raid on the outpost in Tarmiyah, about 30 miles north of Baghdad. It added that a suicide car bombing began the fight, but military authorities declined to give further details.

Witnesses and local authorities offered a fuller picture. The officials spoke on condition of anonymity because they were not authorized to speak to media and feared reprisals.

According to their accounts, at least one car – and possibly others – rigged with explosives was driven on a kamikaze mission at dawn into the concrete outer barriers around the Army base, a former Iraqi police station taken over by American troops late last year.

The blasts ignited stored fuel, they said. Soon, parts of the base were ablaze and under gunfire, but the size of the insurgent force was unclear. It also was not known whether the militants suffered casualties.

U.S. helicopters evacuated wounded soldiers from the compound – located in the center of the town of more than 20,000 residents – while the fight raged, according to the local accounts. By nightfall, U.S. troops had cordoned off streets around the post.

Mohammed al-Askari, spokesman for Iraq’s Defense Ministry, blamed the attack on a cell of al-Qaida in Iraq, which has claimed responsibility for many high-profile strikes.

“It’s their work,” he said.

Residents said the attack may have been prompted by fears that U.S. forces would begin house-to-house searches through the town, which is mostly Sunni but has not been considered a stronghold of militant activity.

The attack came on a day when a string of car bombings and other attacks claimed more than 40 civilian lives in Baghdad and elsewhere in sectarian violence.

In the capital, the bloodshed included at least 11 people killed in a mortar attack on a Shiite enclave and five 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.

On a highway about nine miles northwest of Baghdad, gunmen stopped a minivan and assassinated all 13 occupants, including an elderly woman and two boys, accusing them of opposing al-Qaida in Iraq, police and witnesses said.

In the volatile Sunni city of Ramadi, a suicide car bomber attacked a police checkpoint, killing two Iraqi policemen, Marine spokesman 2nd Lt. Roger Hollenbeck said. Moments later, another suicide car bomber struck a house near the checkpoint, wounding eight women and five children, Hollenbeck said.

Five people, including a 6-year-old boy, were killed by a roadside bomb in the northern city of Tal Afar, local official Najim Abdullah said.