Four U.S. soldiers were killed and two wounded by a roadside bomb near the Syrian border, and four American soldiers were injured when their Humvee crashed during a nighttime operation west of Baghdad, the U.S. military said Saturday. On Friday, insurgents set off at least 17 bombs in Iraq, killing at least 50 people, including three U.S. soldiers, in a series of attacks aimed at shaking Iraq's newly formed government, which takes office on Tuesday. In Baghdad, a drive-by shooting at an Iraqi patrol killed one policeman, police Capt. Talib Thamir said. South of Baqouba, a city 57 kilometers (35 miles) northeast of Baghdad, a roadside bomb aimed at a police patrol killed two civilian bystanders, said Army Brig. Hamid Al-Timimi.