US military officials announced Friday their special forces had captured Samir al-Aziz al-Najim, the regional command chairman of Saddam's Baath Party in eastern Baghdad.

Najim was arrested late Thursday, only hours after the seizure of Saddam's half-brother and former intelligence chief Barzan al-Tikriti.

US commanders, stung by criticism of their failure to nab suspected terrorist mastermind Osama bin Laden and his Afghan protector Mullah Mohammad Omar in their last war, were clearly buoyed by their successes in Iraq.

"The hunting will continue," said US Lieutenant Colonel David Rababy, adding that the Americans would not give up the search for the elusive Saddam himself.

"Anybody wanted by the United Nations or the United States will be caught. Bosnia is a good example, we're still catching them years after the war finished."

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

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

US authorities are remaining tight-lipped about details surrounding Barzan's capture. However, he was seized after the arrest last Sunday of his brother and former interior minister, Watban Ibrahim Hasan.

Both, as well as Najim, were on a US list of 55 most-wanted people from the toppled regime, and both had members of their family inter-married with their leader's siblings, although this did not stop falling-outs.

Barzan was placed under house arrest after objecting to Saddam's wishes that his youngest son Qussay eventually replace him as Iraq's leader. And his daughter refused to marry the president's eldest son, Uday.

Lieutenant Colonel Will Costantini said the military had scoured through thousands of tip-offs prior to the arrest of Barzan and more high-profile captures could now be expected.

Brigadier General Vincent Brooks, Centcom's deputy director of operations, said after the capture that this kind of information had contributed significantly to the operation.

"It's tonnes and tonnes of information which says something about the security situation, in that people are comfortable in coming forward and freely giving out information," he said.

US officials will also be eager to question their latest prisoners closely. Brooks described Najim as a prize catch who "is believed to have first-hand knowledge of the Baath party central structure."

However, Talib Zangana of the Free Iraqi Forces, a group of US-based Iraqi expatriates deployed for the war, said he believed most of the leadership had fled to Syria before the war began.

He said deputy prime minister Tareq Aziz had initially remained behind to fool the world into believing the entire government had stayed in Baghdad and that Saddam could still deliver a blow to the US.

"It is a real mystery how they all disappeared in one night, unless of course they were not here in the first place," Zangana said.

"In my opinion they went to other Arab countries -- Syria -- before the war started and left one or two behind to pretend the full government was here and in full control," he said.

He noted that Barzan's brother Watban had been arrested at the border while attempting to flee into Syria. "That tells you they had the green light to go into Syria."

Zangana warned that Washington had to avoid what happened in Afghanistan where bin Laden and Mullah Omar evaded capture after the Americans invaded.

"That was a real blow to the Americans and we can not allow that blow to happen here," he said.

Rababy and Constantini, the US lieutenant colonels, agreed that further arrests could prove time-consuming but eventually the list of most wanted would face justice.

"With the arrest of Barzan, the US military has proved it will hunt down the bad guy, and it will continue," Rababy added.

SPACE.WIRE