BAGHDAD, Iraq - The U.S. governor of Iraq said today that the transfer of sovereignty to Iraqis must go ahead as scheduled despite the killing of the head of the U.S.-appointed Iraqi Governing Council. In a southern city, nine militiamen loyal to a rebel cleric died in fighting with American forces.

At a memorial service for Izzadine Saleem, who was killed by a suicide bomber Monday at a checkpoint near coalition headquarters, L. Paul Bremer said "terrorists are trying to stop Iraq's march to sovereignty and peace."

"They will not succeed. We must continue the political process leading to an interim government next month and to elections next year," Bremer said, whose American-run coalition is struggling to contain an insurgency in Sunni areas north and west of Baghdad, as well as an uprising in the Shiite heartland to the south.

Early today, U.S. troops killed nine fighters loyal to cleric Muqtada al-Sadr in the holy city of Karbala, said Mutaz al-Hasani, a witness who saw their bodies. Ten Iraqi fighters were also injured in the clashes, which lasted more than an hour on streets near the city's Imam Hussein and Imam Abbas shrines.

U.S. troops and militiamen fought in the Mukhaber district of another holy city, Najaf. Explosions and heavy firing were heard overnight.

A Najaf hotel housing correspondents of the Arab news network Al-Jazeera and a Kuwaiti TV crew was damaged in the fighting. The office of Grand Ayatollah Ali al-Husseini al-Sistani, Iraq's most influential Shiite cleric, also came under fire. There were no casualties in either incident.

Two mortar shells fell today on houses near a compound formerly used by the Iraqi security service in the Baghdad neighborhood of Baladiyat. Three civilians were injured.

Al-Sadr's militia, al-Mahdi Army, launched an uprising against the coalition in early April. Al-Sadr, a fierce opponent of the occupation who is based in Najaf, is wanted on charges of killing a rival moderate cleric last year.

In Mosul, gunmen opened fire today on two civilian cars believed to be carrying foreigners, killing two and wounding another, witnesses said. The attack occurred in the center of the northern city.

Insurgents have targeted civilian foreigners involved in reconstruction in Iraq. In Mosul in March, assailants killed four American missionaries who were working on a water project.

At Saleem's memorial, his family and members the Governing Council gathered inside the so-called Green Zone, which houses the coalition headquarters. Iraqi security forces in desert camouflage carried Saleem's coffin, which was draped with the Iraqi flag, from the hall after the service.

Bremer and other dignitaries, including new Governing Council chief Ghazi Mashal Ajil al-Yawer, kissed and shook hands with Saleem's grieving relatives.

"The enemies of freedom have taken him from his countrymen, from his family and from his friends, and although his loss is greatest for his family and for his country, those of us in the coalition shall miss him as well," Bremer said.

U.N. envoy Lakhdar Brahimi, who is consulting council members and other Iraqis about the makeup of the interim government that will take office after the power handover on June 30, was also at the ceremony.

"We're all working together in order to rebuild Iraq, which he sacrificed his life for," Brahimi said. "We express our cordial sorrow to his relatives and to the Iraqi people."