U.S. Marine Lance Cpl. Jose Murillo of Waltham, Mass., who belongs to the 2nd Marine Division, searches for the Arabic word for husband in a pocket language guide on Friday, while an Iraqi soldier talks to a family in Saadah, Iraq, eight miles from Syria. AP Photo

BAGHDAD, Iraq — A roadside bomb killed 10 Marines and wounded 11 while they were on a foot patrol near Fallujah, the Marine Corps said Friday, in the deadliest attack on American troops in nearly four months.

Thursday’s bomb, which was made from several large artillery shells, struck members of Regimental Combat Team 8 of the 2nd Marine Division near the city about 30 miles west of Baghdad, the Marine Corps said.

In another statement, the Marines reported a U.S. Army soldier also assigned to the 2nd Marine Division died Thursday in a rocket attack near Ramadi. The U.S. command had earlier said four American service members were killed Wednesday, three of them from hostile action and the fourth in a traffic accident.

At least 2,121 members of the U.S. military have died since the beginning of the war in 2003, according to an Associated Press count.

On Aug. 3, 14 Marine Reserve troops from Ohio were killed when their amphibious assault vehicle was blown up by a roadside bomb near Haditha in western Iraq.

Of the 11 who were wounded, seven have returned to duty, the Marine Corps said. It added that Marines from the same unit continue to conduct counterinsurgency operations throughout Fallujah and surrounding areas.

Regimental Combat Team 8 is a part of the II Marine Expeditionary Force based at Camp Lejeune, N.C. The unit has been among the hardest hit in the war. In the nearly three years since the war began, 147 Marines from II MEF have died in combat, according to 2nd Marine Division spokesman Lt. Barry Edwards.

Regimental Combat Team 8 has been in Iraq since the beginning of February.

Fallujah had been a stronghold of the insurgents until U.S. forces, led by Marines, assaulted the city in November 2004. Since then, the U.S. military and the Iraqi government have been working to rebuild it and limit the return of insurgents.

The attack came after U.S. commanders reported a drop in suicide and car bombings as a result of increased U.S.-Iraqi operations.

However, Maj. Gen. Rick Lynch, a coalition operations officer, warned that al-Qaida in Iraq, led by Jordanian terror mastermind Abu Musab al-Zarqawi, will likely step up attacks in the next two weeks to try to disrupt parliamentary elections Dec. 15.

Lynch said suicide bombings declined to 23 in November as U.S. and Iraqi forces were overrunning insurgent strongholds in the Euphrates River valley west of the capital.

Communities along the river are believed used by foreign fighters, who slip into the country from Syria and travel down the waterway to Baghdad and other cities.

Car bombings — parked along streets and highways and detonated remotely — have declined from 130 in February to 68 in November, Lynch said.

However, suicide attacks have not consistently decreased in the past year. After more than 70 such attacks in May, the number fell in August by nearly half and then climbed to more than 50 two months later.

The fatality toll for November was at least 85, which was down from the 96 American deaths suffered in October — the fourth deadliest month since the war began. But it was well above the 49 deaths in September. U.S. monthly death tolls have hit 80 or above during 10 of the 33 months of the war.

There also has been no decline in the past six months in the Iraqi death toll from suicide attacks, according to an AP tally. In November, at least 290 Iraqis were killed in such attacks, more than double the figure from the previous month. The count shows the Iraqi toll ranging from at least 69 deaths in August to at least 356 in September.

In Ramadi, 70 miles west of Baghdad, the U.S. military launched a counterinsurgency operation code-named Operation Shank, a statement said.

“The purpose of the operation is to disrupt a terrorist group that utilizes an area of Ramadi as its base for attacks on local Ramadi citizens, Iraqi and U.S. military,” the statement said. It is the fifth such operation in the area in recent weeks designed to calm the area before the elections.

On Thursday, insurgents allowed a local AP Television News cameraman to film gunmen as they toted automatic rifles and rocket launchers through the streets in central Ramadi. The insurgents appeared to be relaxed and not engaged in fighting. A gunman who did not given his name claimed the insurgents were “controlling the city.”

Lynch denied reports that insurgents had staged major attacks on U.S. forces in Ramadi or had taken control of the town. He said there had been only one rocket-propelled grenade had been fired and there were no injuries.