The Pentagon has ordered U.S. forces here to quickly deploy a U.S.-sponsored opposition militia to Baghdad and other Iraqi cities, U.S. and Iraqi exile sources said today.

The lightly armed Free Iraqi Forces, part of the Iraqi National Congress exile group, will be assigned to help U.S. troops impose order on the chaotic Iraqi capital. But the move to Baghdad also could provide a potentially controversial boost for the Iraqi National Congress as U.S. and Iraqi figures lay the groundwork for an interim administration of the country and, eventually, a new government.

The Iraqi National Congress is led by Ahmed Chalabi, 58, a former banker and longtime exile who has sought to play a leading role in Iraq's postwar future. His advisers made it clear they regarded the shift to Baghdad as an opportunity for him to begin political work in the Iraqi capital.

Chalabi is a controversial figure in Washington. He is closely tied to the civilian leadership of the Pentagon and enjoys support in Congress. But he is distrusted by the State Department and the CIA, whose officials fear he does not command wide support within Iraq.

Last week, the Pentagon flew Chalabi and about 600 fighters to an abandoned air defense facility outside Nasiriyah, where U.S. Special Operations forces have been training them and equipping them with weapons seized from defeated Iraqi forces. In the last couple of days, the force has begun establishing a presence in towns in this area 200 miles south of Baghdad, manning checkpoints and handing out humanitarian aid under the supervision of U.S. troops. Now, the group's leaders are eager to move to the capital.

"We tried it out in Boston and now we're off to Broadway," one of Chalabi's advisers said of the impending departure.

By facilitating Chalabi's move to the capital, where his aides said he would begin creating a representative government, the Pentagon is likely to unsettle other opposition groups. The move could also raise concerns within the Bush administration that the Pentagon is favoring one faction without gauging its level of support.

The INC forces may begin convoying to Baghdad within the next 48 hours. That would put them in the capital before a U.S.-sponsored meeting scheduled here for Tuesday in which various opposition groups, including the INC, are to begin charting the country's future, the sources said.

"We expect this to be the first in a series of regional meetings that will provide a forum for Iraqis to discuss their vision of the future and their ideas regarding the Iraqi Interim Authority," Richard Boucher, a State Department spokesman, said late last week. "We hope these meetings will culminate in a nationwide conference that can be held in Baghdad in order to form the Iraqi Interim Authority."

But exactly how that process will unfold remains unclear and some of Chalabi's aides dismissed Tuesday's meeting as "not very significant," saying Chalabi would not be attending because he had not been invited. Instead, a spokesman said, the group would send another representative. Chalabi's aides said they expected him to be in Baghdad by that time anyway, "doing Iraqi politics," as one adviser put it.

The Supreme Council for the Islamic Revolution in Iraq, a Shiite Muslim opposition group based in Iran, said it specifically opposed Tuesday's meeting and generally opposed any U.S. oversight of an interim administration to replace Saddam Hussein's ousted government.

"We wanted the international community, including Americans, to help us get rid of Saddam's dictatorship, not impose their will on our nation," Abu Eslam Saqir, a spokesman for the group, told the Associated Press in Tehran last week. "We are their friends, not their agents."

Some dissidents have expressed concern that by attempting to orchestrate Chalabi's ascent to power, the United States has rendered Tuesday's meeting irrelevant. But one American supporter of the INC here made no apologies for the standing of the INC at the Pentagon.

"It's good for us and good for Iraq," he said. "The people drawn to him are the people we want."

The Free Iraqi Forces (FIF) has proven itself to be a useful ally in its brief forays into the field, working with local citizens to lead U.S. forces to weapons caches. In a phone call to Chalabi's compound today, Deputy Defense Secretary Paul D. Wolfowitz expressed pleasure at the group's work and progress, a source here said. And Washington clearly wants to accelerate the group's move to Baghdad despite the qualms of some Special Forces trainers about the military readiness of the fighters.

The FIF is composed of volunteers, many of them like Akram Ali Hasson, a 38-year-old from Baghdad who was jailed from 1997 to 2002 after he contacted the INC in northern Iraq.

"I suffered a lot," he said, taking off his boots to show how his captors had removed his toenails. "We dreamed of being a part of the revolution that changed the old regime."

And, he said, he wants to go back to Baghdad to "purify the city."

The FIF plans to place its volunteers in their home towns or regions. A company of about 150 men, all of them former residents of Baghdad, will head to the capital, INC officials said. They will fall under U.S. military command and will work with the Army's V Corps to find and detain Hussein loyalists, gather intelligence in neighborhoods and assist in security and humanitarian missions.

"There has to be an Iraqi element in this campaign," said Zaab Sethna, a spokesman for Chalabi. "They have to take part in the liberation of their country."

But U.S. Special Forces troops found some of the fighters alarmingly undisciplined and of uncertain background. A couple of Iraqi exiles from Lebanon interviewed here said they were released from a detention center for illegal aliens and put on a plane to join the FIF without clearly understanding what they were volunteering for.

About 60 people have attempted to join the force since it arrived from northern Iraq. And a man believed to be a member of Saddam's Fedayeen, a militia loyal to Hussein, was detained today inside the camp after he came in as a volunteer. Other members of the FIF pointed him out and he was questioned by U.S. soldiers, who led him away handcuffed for transportation to a prisoner of war camp nearby.

U.S. and INC officials said they did not know if the man joined with orders to sabotage the group and target Americans or INC members. But infiltration remains a serious security concern because of INC plans to expand the FIF rapidly into a new army working closely with U.S. forces.

"We don't know who some of these guys are," said one U.S. official. "That's a concern for us and for Chalabi."

The Free Iraqi Forces is part of the Iraqi National Congress, an opposition group headed by Ahmed Chalabi, second from left, who has political ambitions in postwar Iraq. Chalabi flew into southern Iraq last week with 600 fighters.