BAGHDAD, Iraq, AP – About 3,500 U.S. and Iraqi troops backed by jets launched a major attack Saturday against an insurgent-held town near the Syrian border, seeking to dislodge al-Qaeda and its allies and seal off a main route for foreign fighters entering the country.

The U.S.-led force sporadically fought militants armed with Kalashnikov rifles and rocket-propelled grenades, and two American service members were wounded, according to The New York Times, which had a reporter embedded with U.S. forces.

Coalition forces supported by tanks and fighter jets dropped 500-pound bombs but met more resistance than expected from insurgents in the town of Husaybah and only managed to take control of several blocks by nightfall Saturday, the Times reported.

At least two U.S. service members were wounded by sporadic enemy fire down alleyways as U.S.-led forces advanced in the town searching house by house, the report said.

U.S. officials describe Husaybah as the key to controlling the volatile Euphrates River valley of western Iraq and dislodging al-Qaeda in Iraq, led by Jordanian terror mastermind Abu Musab al-Zarqawi.

The U.S.-led operation includes about 1,000 Iraqi soldiers, and the offensive will serve as a major test of their capability to battle the insurgents — seen as essential to enabling Washington to draw down its 157,000-strong military presence.

Thunderous explosions shook Husaybah early Saturday as U.S. Marines and Iraqi scouts, recruited from pro-government tribes from the area, fought their way into western neighborhoods of the town, 200 miles northwest of Baghdad, residents said.

Throughout the day, U.S. jets launched at least nine air strikes, according to a U.S. Marine statement.

The coalition forces sometimes found it hard to spot insurgents hiding in the town”s 4,000 homes and called in support from Abrams tanks and fighter jets, the Times reported.

But the soldiers also discovered that many families had fled Husaybah during the past several weeks, having been tipped off about the offensive ahead of time or having assumed that one was likely in the insurgent stronghold, the Times reported.

The U.S. military said Saturday that three more U.S. troops had been killed elsewhere in Iraq.

One soldier was killed Friday by small-arms fire south of Baghdad, and another died the same day when the vehicle in his patrol was hit by a mine near Habaniyah, 50 miles west of the capital. The third soldier was killed Saturday in a traffic accident in southern Iraq.

Those deaths raised to at least 2,045 the number U.S. service members who have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.

Also Saturday, five Iraqi police were killed and three wounded when a roadside bomb exploded in northern Baghdad, hospital officials said.

And 11 members of a Kurdish Shiite family — including an infant — were killed and three wounded when gunmen sprayed their minibus with automatic weapons” fire northeast of Baghdad, police said.

The relatives were returning to their home in the Baghdad area after visiting a family cemetery near Balad Ruz, about 50 miles away. Shiite Muslims traditionally pay their respects to their dead during the three-day Eid al-Fitr holiday, which marks the end of Ramadan and ends for most Shiites on Sunday.

The attack”s motive was unclear, but tensions between Shiites and Sunnis have been on the rise in the area, with extremists from each community targeting the other.

Elsewhere, a 65-year-old male detainee died Saturday of natural causes at a U.S. military prison camp in southern Iraq, the U.S. military announced. Camp Bucca is located near the southern port city of Umm Qasr near the Kuwaiti border.

U.S. commanders hope the Husaybah offensive, code-named &#34Operation Steel Curtain,&#34 will restore control of western Anbar province ahead of the parliamentary election Dec. 15 and enable Sunni Arabs there to vote.

Sunni Arabs form the vast majority of the insurgents, and U.S. officials hope that a strong Sunni turnout next month will encourage many of them to lay down arms and join the political process.

However, some Sunni Arab politicians and tribal leaders complained that the Husaybah operation was endangering civilians in the overwhelmingly Sunni area and could lead to greater instability throughout Sunni sections of the country.

&#34We call all humanitarians and those who carry peace to the world to intervene to stop the repeated bloodshed in the western parts of Iraq,&#34 said Sheik Osama Jadaan, a Sunni tribal leader. &#34And we say to the American occupiers to get out and leave Iraq to the Iraqis.&#34

Husaybah, a poor Sunni Arab town of about 30,000 people, is the first stop in a network of communities that the U.S. military suspects al-Qaeda of using to smuggle fighters, weapons and explosives from Syria down the Euphrates valley to Baghdad and other cities.

Many Husaybah residents are believed to fled the town after weeks of fighting between Iraqi tribes that support the insurgents and those that back the government.

The U.S. military says foreign fighters are only a small percentage of the insurgent ranks, which also include supporters of Saddam Hussein and Sunni Arabs opposed to the Americans and their Shiite and Kurdish allies.

However, foreign Islamic extremists are blamed for many of the spectacular suicide attacks that have killed hundreds of Iraqis in recent months. And foreign extremists are seen as more likely to continue the fight regardless of whether Iraqi Sunnis gain a measure of political power in the coming vote.

Most Sunni Arabs boycotted the Jan. 30 election of Iraq”s current interim parliament, but many members of the minority voted in the Oct. 15 referendum that adopted the country”s new constitution. Many Sunnis also plan to vote in the Dec. 15 ballot, hoping to increase the low number of seats they control in the National Assembly now dominated by Shiites and Kurds.

In Baghdad, Fakhri al-Qaisi, a prominent Sunni politician running on a hardline ticket was shot Saturday as he was driving home. Doctors at Yarmouk Hospital reported him in critical condition.

Meanwhile, suspected insurgents shot and killed a Palestinian working as a security guard in Beiji, 155 miles north of Baghdad, police said. Insurgents frequently target Iraqis and others working for the Americans.

Al-Qaeda in Iraq warned this week that foreign diplomats should leave Iraq or face attacks. The militant group also threatened to kill two kidnapped Moroccan Embassy employees who disappeared Oct. 20 while driving to Baghdad from Jordan.

On Saturday, Arabic language Al-Arabiya TV showed interviews with the families of the Moroccans, begging for their release.

&#34I plead with my brothers, the Muslim mujahedeen in the name of the Islamic law and in the name of justice, because Abdelkrim is a religious man,&#34 said Leqaa Abbas, wife of embassy staff member Abdelkrim el-Mouhafidi.