QAIM, Iraq - U.S. troops battled insurgents holed up in houses and driving explosives-laden vehicles in a second town near the Syrian border Sunday, killing 28 in an expansion of their two-day-old offensive chasing al-Qaida fighters along the Euphrates River valley, the military said. Al-Qaida in Iraq claimed to have taken two Marines captive during the fighting and threatened to kill them within 24 hours unless all female Sunni detainees are released from U.S. and Iraqi prisons in the country. The U.S. military said the claim appeared false. "There are no indications that the al-Qaida claims ... are true," Multinational...