The US military says Abid Hamid Mahmud -- the number four man on the US list of most-wanted Iraqis -- has been taken into custody.
Mr. Mahmud was personal secretary for ousted Iraqi leader Saddam Hussein. US intelligence officials describe him as Saddam's key adviser and one of the few people the Iraqi leader completely trusted.
Only Saddam himself and his two sons rank higher on the list of most-wanted Iraqis.
Officials say Mr. Mahmud could provide a wealth of information about the Saddam regime -- including possibly the location or status of any Iraqi weapons of mass destruction. President Bush cited the alleged weapons as the main justification for the U-S-led invasion of Iraq this March.
The US Central Command says Mr. Mahmoud was captured in Iraq on Monday but did not give the exact location.
US troops have conducted dozens of raids around the country in recent days and detained hundreds of people in a bid to wipe out sporadic resistance. US officials blame Saddam loyalists for attacks that have killed more than 40 American soldiers since May first.
An American general says troops seized huge amounts of cash found during a raid on two farmhouses near Saddam's hometown of Tikrit. Major General Ray Odierno says the troops found eight-point-five-million dollars in American currency, along with smaller amounts of Iraqi dinars, British pounds and euros.
Speaking in Tikrit today (Wednesday) on a video hook-up to reporters in Washington, General Odierno said the cash may have been used to pay bounties for attacks on American soldiers.
The general said his troops also captured nearly 50 people believed to have ties to Saddam's security forces.
Earlier today (Wednesday), one American soldier was killed and another wounded in a shooting attack at a Baghdad gas station.
In a separate incident, US troops shot and killed two Iraqi demonstrators in front of one of Saddam Hussein's presidential palaces, which now serves as the headquarters for coalition forces in Baghdad.