Al-Sadr has been indicted by an Iraqi judge in connection with the murder of a moderate Shi'a cleric one year ago.
U.S. Brigadier General Mark Kimmitt, the deputy commander of coalition military operations in Iraq, has said repeatedly that the mission of U.S. forces is to kill or capture al-Sadr. Yesterday, Kimmitt said al-Sadr could defuse the standoff by surrendering.
"Najaf is not the target," Kimmitt said. "Muqtada al-Sadr remains the target. He can turn himself in, on the basis of a legitimate Iraqi warrant for his arrest, to an Iraqi policeman, where he can seek Iraqi justice. There's no conditionality to that. There's no aspect of that that either requires or necessitates violence. He has it within his hands to prevent the violence."
Phil Kosnett, who heads a four-member team representing the Coalition Provisional Authority in Al-Najaf, said the situation was "explosive." Kosnett, whose team is at a military base in the city, said al-Sadr's militiamen were not in complete control of Al-Najaf.
Correspondents in Al-Najaf said residents were complaining that their lives and livelihoods were at risk. Most shops were closed and streets around the city's shrines were crowded with gunmen instead of religious pilgrims.
Al-Sadr's supporters claim that Iraq's senior Shi'a clerics have backed the uprising they launched earlier this month against the U.S.-led coalition. An Al-Sadr spokesman, Qays al-Khazali, said any assault by U.S. forces in Al-Najaf will signal the start of "revolution all over Iraq."
Although Khazali claimed "moral support" from top Shi'a clerics, Al-Najaf's four grand ayatollahs have all distanced themselves from al-Sadr's actions. A spokesman for Grand Ayatollah Ishaaq al-Fayadh said al-Sadr did not consult the religious authority when he started the uprising or when he created his militia.
Meanwhile, the "St. Louis Post-Dispatch" newspaper reported that five U.S. Marines and dozens of Iraqis were killed in a battle yesterday close to Iraq's western border with Syria.
Latest reports said fighting was continuing today near the town of Husaybah, with U.S. forces sealing off roads to the town and U.S. helicopters providing close air support.
The U.S. newspaper reported that nearly 300 insurgents launched the attack yesterday by setting off a roadside bomb to lure out U.S. troops. The report said more than 20 Iraqi fighters were captured.
A Reuters television crew filmed clashes overnight between members of al-Sadr's militia and Spanish troops in the U.S.-led coalition in Diwaniyah, south of Baghdad.
In the flashpoint city of Al-Fallujah -- where Sunni Muslim insurgents have been surrounded by U.S. Marines for the past two weeks -- correspondents reported relative calm.
The U.S. military said an American soldier was killed and two others injured when their patrol hit an antitank mine near Tikrit on 16 April. A U.S. soldier was also killed by a roadside bomb in Baghdad yesterday.
(RFE/RL and wire reports)