The top U.S. administrator in Iraq declared a Shiite cleric an "outlaw" Monday after his supporters rioted in Baghdad and four other cities in fighting that killed at least 52 Iraqis, eight U.S. troops and a Salvadoran soldier. Later, occupation officials and announced a warrant for Muqtada Sadr arrest. "Effectively he is attempting to establish his authority in the place of the 'legitimate' authority. We will not tolerate this. We will reassert the law and order which the Iraqi people expect," Bremer told a security team meeting convened to discuss how to respond to Muqtada Sadr. This declaration stepped up the confrontation with the 30-year-old cleric, who fiercely opposes the U.S. occupation and is backed by a militia known as the "Al-Mahdi Army." "There is no room for militias in the new Iraq. ... If there are militias that seek to exert control, we will address that head on. And that is clearly what we are doing right now," a senior U.S. official said Monday, according to The AP. Violence broke out Monday morning in another Shiite neighborhood of Baghdad, al-Shula, where followers of the cleric clashed with a U.S. patrol. An American armored vehicle was seen burning, and an Iraqi man was seen running off with a heavy machine gun apparently taken from the vehicle. Apache helicopters then sprayed fire on units of the Mehdi Army, killing at least five people. **Occupation Troops Seal Fallujah*** Meanwhile, U.S. troops on Monday sealed off Fallujah ahead of a major operation code named "Vigilant Resolve." U.S. commanders have been vowing a massive response after Iraqis killed four Americans last Wednesday. Residents dragged the Americans' bodies through the streets, hanging two of their charred corpses from a bridge. Some 1,200 Marines and two battalions of Iraqi security forces were ordered to raid the city. A Marine was killed Monday in Anbar province, where Fallujah is located, the military said. The Marines also closed the main highway from Baghdad to Jordan running through Fallujah. A witness reported that a U.S. helicopter struck a residential area in the city early Monday, killing five people. The bombing damaged five houses, said the witness, according to The AP. **PHOTO CAPTION*** Iraqi Shi'ite supporters of cleric Moqtada al-Sadr celebrate near a burning U.S. Army truck in the Shuala neighborhood of Baghdad April 5, 2004. (Ceerwan Aziz/Reuters)