Four of Washington's 55-list of most wanted Iraqis is now in custody together with Emad Husayn Abdullah al-Ani the father of Iraq's program to make the sophisticated nerve agent VX. who turned himself in to American authorities Friday. American observers said his capture could be an important advance in the U.S. search for chemical and biological weapons inside Iraq.

U.S. officials also have accused al-Ani of involvement with an alleged chemical weapons plant in Sudan with links to al-Qaida.

Military officials say U.S. troops have found no confirmed chemical or biological weapons so far in their searches inside Iraq. No evidence of links between Iraq's government and the al-Qaida terrorist group has been found, either, military officials say.

If al-Ani cooperates with the Americans, al-Ani may be able to provide information on both. He is not one of the "most wanted" Iraqis depicted on the deck of cards distributed by the Pentagon.

Senior Baath Party Leader Arrested: US Military

US-led troops in Iraq have captured a top official of Saddam Hussein's Baath Party, Samir Aziz al-Najim, Brigadier General Vincent Brooks announced.

"Special operation forces last night captured another key member of the regime, Samir Aziz al-Najim, one of the top 55 members of the regime," Brooks told reporters at the US Central Command war headquarters in Qatar.

The capture of Najim, the regional command chairman of the Baath party in eastern Baghdad, follows the seizure of Saddam's half-brother and former intelligence chief Barzan al-Tikriti on Thursday.

"Najim was handed over to coalition forces by Iraqi Kurds near Mosul in northern Iraq," the general said, adding that Najim "is believed to have first-hand knowledge of the Baath party central structure."

To date, US-led forces in Iraq have captured four of the 55 people who figure on a list of most-wanted Iraqis.

Najim was number 24 on that list and was displayed as the four of clubs in the deck of playing cards on which Central Command displayed the wanted men.

The other two in US custody are Watban Ibrahim Hasan, another half-brother of Saddam Hussein, who was arrested on Sunday, and General Amer al-Saadi, Saddam's top weapons advisor, who surrendered last Saturday.

The capture of the four men has fueled hopes that Washington's list of most-wanted from the regime will eventually be tried.

Key Developments in the War Against Iraq

*_ Thousands of Iraqis marched in downtown Baghdad to demand a rapid U.S. troop withdrawal.

*_ Iraqi opposition leader Ahmad Chalabi, in his first public appearance in Baghdad, said he expects an Iraqi interim authority to take over most government functions from the U.S. military in "a matter of weeks rather than months."

*_ The Pentagon announced that the remains of one of two Air Force pilots declared missing after their F-15 fighter jet was shot down April 7 have been recovered and identified as Capt. Eric B. Das of Amarillo, Texas.

*_ North of Baghdad, U.S. troops attacked an airfield after an unmanned surveillance plane captured images of paramilitary fighters who appeared to be loading ammunition into pickups, intelligence officers said. Central Command said the Army destroyed eight vehicles and captured more than 30 Iraqi fighters.

*_ Interpol announced it is sending a special team to Iraq to help track down pillaged art treasures. FBI agents also have been sent to Iraq to help recover the stolen antiquities.

*_ The seven former POWs appeared together at a U.S. military hospital in Germany. They said they looked forward to returning home and called for prayers on behalf of U.S. troops still in Iraq.

PHOTO CAPTION

Barzan al-Tikriti (2nd L), half-brother of Iraqi President Saddam Hussein, with dignitaries. The former advisor to Saddam Hussein has been arrested by coalition forces near the Syrian border. (AFP/File/Jamal Nasrallah)