Excerpt - BAGHDAD, May 20 (Reuters) - Iraq's army moved on Tuesday to take control of Baghdad's Sadr City, power base of Shi'ite cleric Moqtada al-Sadr, in another step to stamp government authority over areas previously outside its control. A spokesman for Iraqi security forces in Baghdad, Major-General Qassim Moussawi, said soldiers had launched "Operation Peace" in the sprawling eastern Baghdad slum early on Tuesday. Iraqi soldiers, who previously controlled only the outer perimeter of Sadr City, advanced deep into the poor suburb, home to 2 million people, without meeting any opposition, he said. "We are taking control of three-quarters...