stronghold in central Iraq Baghdad, Oct 6, SPA -- U.S. and Iraqi forces sealed offroads to an insurgent stronghold south of Baghdad onWednesday and insurgents bombed two bridges in an apparentbid to hinder troop movement as pro-government forces triedto retake control of the region ahead of nationalelections. On Tuesday, Iraq's Interim Prime Minister Ayad Allawi saidthe tempo of attacks against insurgent strongholds wouldincrease but acknowledged that the security challenge was a"source of worry." "I don't want to deny the impact of the securitysituation nor minimize the size of the challenges weface," Allawi said during a speech in Baghdad. On Wednesday, U.S. soldiers and Iraqi National Guardsmenwere sealing off the roads leading to Qasir town in thearea of Youssifiyah, preventing anybody from going in orout. A day earlier, insurgents detonated a car bomb inYoussifiyah, (20 kilometers) 12 miles south of the capital,as the Iraqi National Guard was conducting raids, killingone civilian and wounding 13 Iraqis. Two explosions _ one a car bomb another a roadside bomb _hit two bridges in the area Wednesday, residents said, inan apparent attempt by insurgents to affect the movement ofIraqi and U.S. forces.--SPA1353 Local Time 1053 GMT www.spa.gov.sa/208511