U.S. troops found the warhead, which is about as long as a baseball bat and as big around as a coffee can, during routine operations to secure the airfield in Kirkuk. It was marked with a green band which, military sources told CNN, is the universal symbol for chemical weaponry. 

Two separate "improved chemical agent monitor" (ICAM) tests showed trace amounts of a nerve agent in two spots on the warhead -- at the rear and in the middle where there is a screwed-down circular area about the size of a quarter. 

A former Iraqi air force colonel, claiming to be the former base commander, came to Kirkuk on Friday and told military officials he knew of 120 missiles within about an 18-mile radius of Kirkuk -- 24 of those carrying chemical munitions, according to an army intelligence posting at the airfield's military headquarters. 

Meanwhile, Lt. Gen. Amir al-Saadi, Saddam Hussein's top science adviser and Iraq's point man for the last round of U.N. weapons inspections, surrendered to coalition troops Saturday in Baghdad, according to a senior military official at U.S. Central Command. He was No. 55 on the U.S. list of 55 most-wanted Iraqis. 

German television network ZDF helped arrange al-Saadi's surrender and filmed it at the general's request to assure his safety. 

ZDF said al-Saadi left his Baghdad home with his German-born wife Helga and surrendered to a U.S. officer, who escorted him away. Al-Saadi also granted the network an interview, and told its reporter that he had no information about other members of the dictatorial regime -- including Saddam Hussein -- and insisted, as he had during the inspections regimen, that Iraq has no weapons of mass destruction. 

Coalition forces are working to restore order in Baghdad, and across Iraq, after days of looting and lawlessness triggered by the sudden collapse of Saddam's regime. 

CNN's Martin Savidge said some of the looting in Baghdad had subsided Saturday, with much of it concentrated on government officials' homes. 

He added that stores were reopening, and there were more people on the streets. Many were searching for telephones to inform relatives outside Iraq that they were OK. 

A dusk-to-dawn curfew did not seem to prevent gunshots and chaos overnight, CNN's Michael Holmes reported. Fires burned in several buildings. Huge explosions could be heard overnight, the sounds of coalition troops destroying munitions. Gunfire was also heard on the southern edge of the city 

The U.S. military is interviewing retired Iraqi police officers -- including a general -- to create a legitimate police force in the Iraqi capital, CNN has learned. 

Two of the retired police officers, speaking on the Arabic-language, Qatar-based news network Al-Jazeera, urged former Baghdad police officers to help build a new force. 

"I call upon you to go and report to your stations," Mohamed Bandar said. "We are all volunteers; we need to help our people." 

Bandar also asked for assistance from Iraqi tribal leaders, saying the coalition should not ignore the tribesmen when forming a police force for Baghdad. 

In Mosul, a city in northern Iraq, neighborhood watch groups and coalition forces were patrolling the city to maintain calm, said Brig. Gen. Vincent Brooks of the U.S. Central Command. 

British forces could start patrols with local Iraqi police officers in the southern city of Basra in the next few days to control looting and civil disorder, said British Central Command spokesman Capt. Al Lockwood, at Central Command headquarters in Doha, Qatar, on Saturday. 

The Pentagon approved a plan Friday under which the U.S. military would ask other nations to send nonmilitary police forces to Iraq, officials said, adding that they had always planned to ask other countries to provide security forces when most of the combat was over. 

The 2nd and 3rd Brigades of the U.S. Army's 101st Airborne Division began their second day of foot patrols in Baghdad on Saturday, CNN Correspondent Ryan Chilcote reported. 

The U.S. Marines, who pushed into the center of the city on Wednesday, will leave Baghdad Saturday and begin moving north, officials with the U.S. Central Command told CNN's Tom Mintier. 

The Central Command also said that U.S. Army's 4th Infantry Division crossed into Iraq on Saturday from Kuwait, about two weeks after they were deployed.

The military had hoped to transport the 4th Infantry Division's vehicles and troops over land in northern Iraq, but the United States failed to reach an agreement with Turkey about using its military bases to gain access to northern Iraq. 

Southeast of Baghdad, Marines moved into the city of Kut without firing a shot Saturday. CNN's Art Harris said that the Marines expected trouble, but were instead "welcomed like liberators." 

Other developments
• United Nations relief agencies expect to return to Iraq by Monday to resume their humanitarian efforts. The U.N. pulled its staff out of the country on March 18. 

• Coalition forces took 59 men into custody Friday after they were found to be carrying about $600,000 and letters offering rewards for killing U.S. soldiers, Brooks said. The men were on a bus stopped at a military checkpoint in western Iraq. 

• An Iraqi who surrendered to U.S. Marines Saturday told them he performed plastic surgery on Saddam and his relatives, and knows where the family has fled, Marines told CNN's Martin Savidge. The man didn't say he knew the whereabouts of the former Iraqi leader. 

• Former prisoner of war U.S. Army Pfc. Jessica Lynch left a U.S. military medical center in Germany on Saturday to return to the United States, hospital and military officials said. Lynch, 19, was rescued by U.S. forces from a hospital in Nasiriya, Iraq, 10 days after she was captured by Iraqi forces March 23. 

• At Fort Bliss, Texas, nine soldiers who were killed early in the war were honored at a memorial ceremony Friday. 

• U.S. military leaders issued a most-wanted list of former Iraqi leaders they said must "be brought to justice." Coalition troops in the field have been given a list of 52 former regime leaders in several forms -- one of them a deck of playing cards with images of the people's faces and job descriptions -- "to ease identification when contact does occur," Brig. Gen. Vincent Brooks said Friday.

• The leaders of Russia, France and Germany have called for a central United Nations role in the reconstruction of Iraq. Russian President Vladimir Putin, German Chancellor Gerhard Schroeder and French President Jacques Chirac were holding their second day of talks in St. Petersburg on Saturday. The discussions have focused on Iraq.