BAGHDAD, Iraq – Ahmad Chalabi, a leader of Iraq’s exiled opposition, surfaced for the first time in the smoldering heart of Baghdad and said Friday he expects a provisional government to take over most powers in “weeks rather than months.”

“The United States of America does not want to run Iraq,” said Chalabi, whose Iraqi National Congress was heavily financed by Washington in recent years. “That is the policy of the United States, that’s what President Bush has said, and I believe him.”

This first appearance by the longtime exile, little known inside Iraq, came not at a public rally but before international journalists at an exclusive social club, behind a shield of U.S. armor and militiamen known as the Free Iraqi Forces.

Across the Tigris River earlier in the afternoon, after the Friday prayers at the Abi Hanifah Mosque, thousands of Muslims protested the U.S. military presence in the Iraqi capital, barely a week after American tanks and troops toppled the regime of Saddam Hussein.

Spotting U.S. soldiers on the street, marchers waved their fists and chanted, “America is God’s enemy!”

The American military was showing no signs of an early withdrawal, however. In fact, the Marine units controlling east Baghdad were preparing a transition to the U.S. Army, which already controls the city’s western half.

Since seizing Baghdad, the U.S. military has issued scant information about day-to-day administration of the city. On Friday, however, a Marine spokesman said electricity was expected to be restored to most areas “in the next couple of days.”

The lack of power and clean water has fed anti-American resentment in this city of 5 million people.

Chalabi, a member of a prominent southern Shiite family who has lived outside Iraq since 1958, arrived in Baghdad on Wednesday and established a headquarters at neighboring social clubs — one a former hangout of Saddam’s two sons — in the affluent al-Mansour district.

Opposition representatives met in southern Iraq on Tuesday to discuss ways to form an interim government. Many Iraqis boycotted that meeting to protest U.S. plans to install a retired general, Jay Garner, as head of a temporary administration.

Chalabi, who did not personally attend but sent a representative to the meeting in the southern city of Ur, was asked Friday about the progress toward an Iraqi interim authority.

“The stages I foresee are, first, reconstruction of basic services, done by Jay Garner,” he replied. “I expect this step to take a few weeks.”

Then, he said, “the Iraqi interim authority will be chosen by Iraqis and will take over the business of government.”

Ultimately, Chalabi said, the U.S. military will have just three functions in Iraq: to eliminate any weapons of mass destruction, to destroy the old regime’s “apparatus of terror,” and to disarm the former government’s military.

Officials in Garner’s organization said Chalabi’s timetable for the appointment of an interim authority was in line with their own expectations. They declined to be more specific.

Chalabi, whose fractious Iraqi National Congress is an umbrella group of political, religious and ethnically based anti-Saddam movements, was vague on the details of transition, which are expected to be largely determined by the Americans.

He said he expects it will take two years to organize a constituent assembly, produce a draft constitution, submit the draft to a referendum and conduct free elections.

Chalabi is a controversial figure in opposition circles, in part because of financial scandals in his past. He reiterated that he is not a candidate to be the leader of Iraq, and did not indicate that he favored any individual for the leadership.

But Hamid al-Bayati, the British representative of a key anti-Saddam opposition group, the Supreme Council for the Islamic Revolution in Iraq, said Chalabi might be hoping to run for office eventually.

Mahmoud Osman, a Kurdish leader living in London, said Chalabi looked like “an American propagandist.” “Chalabi is trying to look like the one who knows everything and the details of American policies, and I don’t think that it will work out,” Osman said.

The day’s two major events — the sealed-off news conference by the U.S.-supported Chalabi, and the anti-American protest by ordinary Iraqis who probably had never heard of him — underscored the deep political uncertainties facing this country.

Some Iraqis were taking no chances, among them the tribal chieftains and others who called on a Chalabi lieutenant, Mohammed Mohsen al-Zubaidi, who has proclaimed himself Baghdad’s governor without any popular sanction. On Friday, they went to the Palestine Hotel — where al-Zubaidi set up an office in an empty lobby shop — to pay their respects.

Staff Sgt. John Jamison, a 1st Marine Division spokesman, was unimpressed.

“He seems to be a self-proclaimed mayor,” he said. “There is no one right now in government. Only those two generals” — of the Army and Marines now holding Baghdad.