Three U.S. soldiers were killed in a mortar strike in the restive western city of Ramadi and another died in a bombing, authorities said Sunday, as tensions flared among Iraqi officials about reported clashes in a religiously mixed area south of the capital. The incidents, capping a week of resurgent attacks, underscored the precarious security situation more than two years after the U.S.-led invasion that toppled the government of Saddam Hussein.Full Story