Warplanes hammered elite Republican Guards defending Baghdad on March 25, 2003 as U.S. armored columns, slowed by blinding sandstorms, closed in for the decisive battle for the Iraqi capital. In southern Iraq U.S. Marines finally punched past Iraqi resistance to cross the Euphrates river at Nassiriya. But they met a fresh ambush on the road north, despite an air strike that killed at least 30 Iraqis apparently heading into battle.