An aide to Mohammad Bahr al-Uloum, a member of the U.S.-installed Iraqi Governing Council, said Ayatollah Ali al-Sistani, regarded as Iraq's most powerful cleric and a rival of Sadr's, supported the Iraqi seminary's appeal.

"The Hawza (seminary) is unanimous on this," the aide said.

"We asked Moqtada (al-Sadr) to stop resorting to violence, occupying public buildings and other actions that make him an outlaw. He insists on staying on the same course that could destroy the nation."

He said Moqtada had refused to meet a religious and tribal delegation at the main mosque of Kufa, near the holy city of Najaf, where he is staging a sit-in with armed followers.

"The delegation met Moqtada's aides, who did not express interest in relying on wisdom and patience," the aide said.

U.S. authorities occupying Iraq issued an arrest warrant for Sadr Monday in connection with the murder of a senior Shi'ite cleric a year ago.

Iraq's de facto U.S. governor Paul Bremer termed Sadr an outlaw Monday, a day after battles between Sadr's militia and U.S.-led coalition troops in Baghdad and near Najaf killed 48 Iraqis, eight American soldiers and one Salvadoran soldier.

For the past week, Sadr has been at the head of violent anti-American protests. His followers have sworn to fight back if attempts are made to arrest him.

Unlike the Shi'ite religious establishment, which has historic alliances with Iraq's merchant class and has cooperated with the U.S.-led occupation, Sadr has flatly denounced the occupation and demanded withdrawal of U.S. troops.

His brand of nationalistic Islam appeals mainly to young poor Shi'ites who grew up under a crippling economic embargo and repression by the former Baathist government.

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