''There are no indications that the Al Qaeda claims . . . are true," said Multinational Force West, the command in the region. Command officials added they were conducting checks ''to verify that all Marines are accounted for."
Even as the fighting continued, political differences among Iraqi leaders deepened ahead of the crucial Oct. 15 national vote on a new constitution. Iraq's Kurdish president, Jalal Talabani, called on the Shi'ite prime minister to step down over accusations he is monopolizing power in the government and ignoring his Kurdish coalition partners' demands, a spokesman for Talabani's Patriotic Union of Kurdistan said.
The US military says Al Qaeda in Iraq, the country's most fearsome insurgent group, has turned the area near the border into a ''sanctuary" and a way station for foreign fighters entering from Syria.
In Karabilah, Marines clashed with insurgents who opened fire from a building yesterday in a firefight that killed eight militants, the military said.
The move into Karabilah widened the sweep launched a day earlier by 1,000 Marines, soldiers, and sailors, starting with nearby Sadah -- a tiny village about 8 miles from the Syrian border.
Most of the militants appeared to have slipped out of Sadah before the force moved in, and hundreds of residents from the village fled into Syria ahead of the assault.
There was ''virtually no opposition" in Sadah, said the Marine commander in western Anbar Province, Colonel Stephen W. Davis.
Davis said at least 28 militants were killed in fighting yesterday, bringing the two-day toll among insurgents to 36. There have been no serious US casualties in the operation, he said.
US forces are aiming to clamp down on insurgents ahead of the Oct. 15 vote. Al Qaeda in Iraq and other groups in the Sunni-led insurgency have launched a wave of violence to wreck the vote, killing more than 200 people over the past week.
The US operation in the Syrian border region is the fourth since May. But US troops are too scattered and Iraqi forces too few to impose permanent control in the area, which is the size of West Virginia.
Militants have fled past assaults only to move back in once the bulk of US forces leave.
