At a Baghdad mosque, thousands of worshippers protested the U.S. military presence following a sermon in which a Muslim cleric urged the Americans to leave before they were forced out. 

The latest of Saddam's inner circle to be captured was Samir Abd al-Aziz al-Najim, a senior leader of the shattered Baath party who was handed over to U.S. forces overnight by Iraqi Kurds near the northern city of Mosul. Al-Najim was on the list of 55 former Iraqi leaders whom the U.S. military wants killed or captured. 

It was the second straight day that Brig. Gen. Vincent Brooks of U.S. Central Command opened his daily briefing by announcing the capture of a senior official. Thursday, U.S. special forces grabbed Barzan Ibrahim Hasan, a half brother of Saddam and a former head of Iraqi intelligence. 

Al-Najim is a member of the Baath party's Regional Command, its top decision-body. He was oil minister until earlier this year, served as Iraq's ambassador to Egypt, Turkey, Spain and Moscow, and was Saddam's chief of staff for several years after the 1991 Gulf War. 

The attack north of Baghdad by an armored unit of the 4th Infantry Division came after intelligence data from an unmanned reconnaissance plane indicated that paramilitary fighters were loading ammunition into pickup trucks. Brooks said the Army unit destroyed eight vehicles and captured more than 30 fighters. 

Baghdad itself was reported calm on Friday, the Muslim holy day. But one leading cleric, Ahmed al-Kubeisy, used his sermon to criticize the American "occupation" and said U.S. soldiers should leave the country soon before Iraqis expel them. 

"You are the masters today," al-Kubeisy said to cheers from, worshippers at the Abu Haneefa al-Nu'man Mosque . "But I warn you against thinking of staying. Get out before we force you out." A large demonstration followed. 

In Landstuhl, Germany, the seven American soldiers freed from Iraqi captivity last weekend made a brief public appearance on the balcony of their military hospital. Hospital officials said all seven are doing well, though three suffered gunshot wounds, and all are expected to return home Saturday. 

Speaking for his six comrades, Chief Warrant Officer David S. Williams, 30, of Orlando, Fla., thanked Americans for their support. 

"We're looking forward to coming home as soon as we possibly can," he said. "I'd just like to remind everyone to say a special prayer for all those who are still fighting on the American fence. And, God bless America." 

In Washington, FBI Director Robert Mueller said experts from his agency have been deployed in Iraq to help find the antiquities stolen during recent looting of Baghdad museums and the national library. Interpol, the Paris-based international police organization, said Friday it also would send a team to Iraq to assist that effort. 

A separate contingent of FBI agents is reviewing the trove of regime documents recovered by U.S. troops in Iraq, looking for possible leads in the campaign against international terrorism and the hunt for weapons of mass destruction, Mueller said. 

Even as the search for illegal weapons expanded, Defense Secretary Donald H. Rumsfeld expressed doubts that any would be found until Iraqis provide the crucial tips. 

"I think what will happen is we'll discover people who will tell us where to go find it," Rumsfeld said. "It is not like a treasure hunt where you just run around looking everywhere, hoping you find something." 

As many as 1,000 people are believed to be involved in the U.S.-led effort to find illegal weapons, and thus corroborate prewar allegations made repeatedly by the Bush administration. U.S. troops have found suspicious chemicals and facilities at several sites, but tests on the materials have proved negative or inconclusive. 

Hans Blix, the chief U.N. weapons inspector for Iraq, has urged the U.S.-led coalition to allow his team back into the country, saying it would increase the credibility of any weapons discoveries. The team left Iraq just before the war after several months of inspections. 

In northern Iraq, American officials were examining a tract of about 1,500 unmarked graves near Kirkuk. Thousands of Kurdish men in that region disappeared during Saddam's rule - part of a drive to crush an independence movement - but it was not immediately clear whose corpses were in the graves. 

In Baghdad, Iraqi engineers supported by U.S. troops said they hope to have the city's biggest power plant going by Saturday. The lack of basic services such as power and water, along with the widespread lawlessness, has fueled resentment of the American forces. 

The 10-story Ministry of Information building was on fire at midafternoon, flames shooting from the top. U.S. soldiers surrounded the building as looters tried to carry off remaining booty; an Army loudspeaker broadcast a warning, in Arabic, to leave the area "or there will be consequences." 

Elsewhere in the capital, Marines guarding a looted laboratory near the Ministry of Health said they had been told anyone who enters risks contracting diseases because of broken bottles. 

A sign warned, "Danger - Keep Out. The ground is infected with HIV, cholera, polio and other diseases." 

Another site devastated by looting was Baghdad's zoo - thieves stole birds and some mammals and opened the monkey cages, setting them free to roam the city. On Friday, a truck set out from Kuwait with seven tons of meat, vegetables and dried food for the animals, whose keepers fled when fighting broke out.