Iraqi opposition leader Ahmad Chalabi, in his first public appearance in Baghdad, said Friday he expects an Iraqi interim authority to take over most government functions from the U.S. military in "a matter of weeks rather than months."

Chalabi, head of the Iraqi National Congress, was vague about how an interim government would be selected. At a news conference, 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.

U.S. officials have said the process will include a series of meetings by representatives of different Iraqi groups, the first of which took place Tuesday in the ruins of the ancient Sumerian city of Ur in southern Iraq.

Chalabi said that once such an authority is established, the U.S. military will have three functions: to eradicate any weapons of mass destruction, to dismantle the ousted regime's "apparatus of terror," and to disarm the previous regime's army.

In the near term, Chalabi said he foresaw "first reconstruction of basic services, done by Jay Garner," the retired American general, designated to run the military administration.

"I expect this stage to take a few weeks," he said.

After that, he said, "an Iraqi interim authority will be chosen by Iraqis and take over the business of governing."

Then, a proposed constitution will be debated by a constituent assembly and then voted on in a general referendum and be the basis for general elections, Chalabi said.

"I expect this process will take two years," he said.

"The United States of America does not want to run Iraq," Chalabi added. "That is the policy of the United States, that's what President Bush has said, and I believe him."

Asked whether the United Nations should play a political role in the new Iraq, Chalabi cited the lack of U.N. support for the invasion to topple the regime of Saddam Hussein and said, "I don't think the United Nations is capable in Iraq to play a major role."

He said an interim authority should be appointed "sooner rather than later, a matter of weeks rather than months."

Officials in Garner's organization said on condition of anonymity that Chalabi's timetable for the authority's appointment was in line with their own expectations. They declined to give a more specific timeline.

As the head of a London-based umbrella group, the Iraqi National Congress, Chalabi has been touted by some as a possible political leader in a new government. He enjoys strong support from the Pentagon and others in the Bush administration.

However, he is little known within Iraq after decades in exile, and has said a number of times he is not a candidate for the top job.

Since arriving Wednesday, Chalabi's entourage has established a headquarters at two neighboring social clubs in Baghdad's affluent Al-Mansour district.

The properties are under close guard by both American armored units and members of the new "Free Iraqi Forces," a militia-like contingent sponsored by Chalabi's Iraqi National Congress that entered Baghdad for the first time in recent days.