The U.S. military launched a major combat operation Friday as 1,000 Marines and Iraqi soldiers fanned out to track down insurgents and foreign fighters in a volatile western province straddling Syria.
Operation Spear started in the pre-dawn hours in Anbar province, the military said. The area is where U.S. forces said it killed about 40 militants in airstrikes in Karabilah on June 11.
The operation began a day after Air Force Brig. Gen. Don Alston called the Syrian border the "worst problem" in terms of stemming the influx of foreign fighters into Iraq. Syria is under intense pressure from Washington and Baghdad to tighten control of its porous 380-mile border with Iraq.
The Marines have lost 11 men and two sailors in the past week in separate incidents around Anbar.
In other developments:
On June 11, the Marines engaged the insurgents after the militants took control of a road just outside Karabilah near the Iraqi-Syrian frontier city of Qaim, about 200 miles west of Baghdad.
During that battle, insurgents killed 21 people, beheading three of them. Those bodies, found June 10, were believed to belong to a group of missing Iraqi soldiers.
During the airstrikes, Marine aircraft fired seven precision-guided missiles at insurgents armed with AK-47 assault rifles, machine guns and rocket-propelled grenade launchers. No U.S. troops or civilians were injured.
On Thursday, Alston blamed Iraq's recent spike in bloodshed on Jordanian-born terrorist leader Abu-Musab al-Zarqawi, who purportedly condoned the killing of fellow Muslims and denounced the country's majority Shiites as collaborators with the Americans.
Alston took aim at al-Zarqawi, saying the leader of al Qaeda in Iraq is most responsible for the nearly 1,100 violent deaths since the Shiite-led government took office seven weeks ago.
Al-Zarqawi's hope to provoke a sectarian war suffered a setback Thursday when the Shiite-led parliament and leaders of the disaffected Sunni Arab minority, which is believed to provide the backbone of the insurgency, agreed on a process for drafting Iraq's constitution.
Alston's focus on al-Zarqawi, whose small group is blamed for many of the bloodiest attacks and hostage-takings in Iraq, apparently was aimed at reinforcing growing dissatisfaction among Iraqis over insurgents targeting civilians. He said that anger has brought an increase in calls to tip lines.
He said tips to Iraqi authorities resulted in Tuesday's arrest of Mohammed Khalaf, also known as Abu Talha, who was al Qaeda's leader in Mosul, 225 miles northwest of Baghdad.