The Army's 4th Infantry Division, currently based around Baghdad International Airport, will eventually relieve Marines in northeastern Baghdad and start looking for weapons of mass destruction and providing stability to the area, a military official says. 

Troops from the 3rd Infantry Division and the 101st and 82nd Airborne divisions - among the first wave of U.S. ground troops in Iraq - could start leaving Iraq as early as June, the official said Friday. 

The Army's 1st Armored Division will begin moving into Iraq within the next few weeks, the official said. 

The U.S. Central Command announced Saturday that officers from Iraq's newly revived police force arrested Iraq's former finance minister - one of the 55 ex-leaders on the U.S. most-wanted list - and handed him over to the Marines. 

Hikmat Mizban Ibrahim al-Azzawi was nabbed Friday in Baghdad, the command said. He had also served as a deputy prime minister. 

Meanwhile, the surrender of one of Saddam Hussein's top chemical weapons scientists could be an important advance as troops step up the search for weapons of mass destruction. 

Emad Husayn Abdulla al-Ani turned himself in to U.S. authorities inside Iraq, an American official said. Al-Ani has been called the father of the Iraqi program that made tons of the nerve agent VX, and he was accused by U.S. officials of involvement with a chemical plant in Sudan also linked to terrorist leader Osama bin Laden. 

Although al-Ani was not on a list of Iraqi officials being sought by the Americans, his capture could be a significant boost to the hunt for any Iraqi chemical, biological or nuclear weapons. Other captured Iraqis involved in Saddam's weapons programs include Lt. Gen. Amer al-Saadi, the former Iraqi leader's top science adviser, who surrendered in Baghdad. Jaffar al-Jaffer, described as the father of Iraq's nuclear weapons program, turned himself in to authorities in the United Arab Emirates, officials have said. 

U.S. experts have found no confirmed caches of chemical or biological weapons in Iraq so far, military officials say. Eliminating weapons of mass destruction from Iraq was the principal reason President Bush and other administration officials cited for invading Iraq. 

Defense Secretary Donald H. Rumsfeld said this week he doubted U.S. teams would find weapons of mass destruction without help from Iraqis who know about Saddam weapons programs. 

Al-Ani would fit that description. Iraq admitted to U.N. weapons inspectors it had produced 3.9 tons of VX nerve agent in the 1980s but had destroyed it, a claim never verified by inspectors who concluded Iraq may have made much more of the deadly chemical. Tests showed Iraq had filled some munitions with VX, inspectors said. 

Al-Ani once headed the research and development program at Iraq's Muthanna State Establishment, a key chemical weapons laboratory, and later headed Iraq's Fallujah 2 chemical weapons plant. 

In 1998, U.S. officials said they intercepted phone calls between al-Ani and executives of the Shifa Pharmaceuticals plant in Khartoum, Sudan. Then-President Clinton alleged that the plant was making a key precursor chemical used in manufacturing VX, a claim that was never independently substantiated. 

American officials said the Shifa executives who had contact with al-Ani also had ties to bin Laden, the al-Qaida leader. But they conceded they did not know if al-Ani or other Iraqis knew of Shifa's links to bin Laden, which the U.S. officials said were "fuzzy." 

The United States destroyed the plant with cruise missiles shortly after al-Qaida bombed U.S. embassies in Kenya and Tanzania. Officials of the Shifa plant and Sudan's government denied it was involved in chemical weapons work. Iraq denied helping Sudan with chemical weapons and said al-Ani had no contacts with Sudanese government officials. 

U.S. military officials say American troops have not found any evidence linking Saddam's regime with al-Qaida. Al-Ani likely will be asked about whether he knew of any such links.