Tikrit, Iraq ? U.S. forces hunting top and midlevel leaders of the Iraqi insurgency are close to unraveling a network of five powerful clans that have funneled money, weapons and instructions to street gunmen and bombmakers, according to a U.S. Army commander.

A decline in attacks on U.S. forces in recent weeks has allowed troops time to track the top level of the insurgency and the former regime — an effort capped by the arrest of Saddam Hussein earlier in December near Tikrit, Saddam’s hometown.

Over months of intelligence gathering that began with the arrests of an outer circle of bodyguards close to Saddam, U.S. forces say they have reduced the ranks of rebel leaders coming from five powerful families. Those clans have largely directed the insurgency around Tikrit, the hub of a volatile zone to the north and west of Baghdad where most of the attacks on coalition forces have been launched, said Lt. Col. Steve Russell of the Army’s 4th Infantry Division.

“We have seen the grip of the enemy on this town slip more and more as the months have gone by,” Russell said in an interview Saturday with several news organizations, including The Associated Press.

Commanders tracking the insurgents’ top support and guidance networks began to peel back the layers in June with the arrest of Saddam’s personal secretary and de facto chief of staff, Abid Hamid Mahmoud, No. 4 on the list of 55 top fugitives among the former regime and its supporters. His functions were subsequently divided between about half a dozen brothers among the five extended families. One of those men was captured, too, and eventually led U.S. forces to Saddam’s underground shaft dug out in a muddy farmhouse yard. His identity has been kept secret.

“We have decimated several of these families. A great many have been captured from these families. In some cases they are dead,” said Russell, who declined to name the clans. The capture of Saddam was the net result of the trove of uncovered information on these tribes, and it seems to have deprived insurgents of an important symbol to rally around, he added.

“I think he was the bouncing ball everybody wanted to follow,” Russell said of Saddam.

Except for a few days of violent street protests that followed his capture, fighting has fallen off dramatically around Tikrit.

Fugitive leaders

Those top leaders still at large remain tough to find, mainly because of large families. With several wives, some of them have more than a dozen children who own many properties of their own, giving the fugitives numerous places to hide.

A U.S. soldier checks an Iraqi's driver's license against a list of names of suspected insurgents at a checkpoint in Samarra. Saturday's check was part of growing American efforts to trace how ammunition and money are being provided in attacks against U.S. troops.

Russell’s forces have mapped a complex family tree of 250 top and midlevel activists from the five clans. Some have been captured, killed or have fled the country, leaving just a handful, Russell said, without giving exact figures.

Russell cautioned that while the arrests of top and midlevel leaders have deprived street fighters of important support and have been followed with a decrease in attacks, their capture alone is not likely to bring an end to the insurgency. U.S. officials have also suggested that the rebel ranks include cells operating independently of any centralized command.

“Whether or not it will be completely done when the chart’s checked off, no, that’s overstating it,” Russell said. “But when they are taken out of the equation we do see improvement.”

Attacks persist

Other commanders acknowledge that the rebels — numbering in the thousands by some estimates — are not through fighting.

Roadside bombs in separate guerrilla attacks killed two U.S. soldiers and two Iraqi children on Sunday, including one explosion that went off in a densely populated part of Baghdad.

In Sunday’s first attack, a bomb planted beside a road in Baghdad killed two Iraqi children and an American soldier and wounded 14 people, said U.S. Army Sgt. Patrick Compton of the Army’s 1st Armored Division. The wounded include five American soldiers, their Iraqi interpreter and eight members of the Iraqi civil defense corps.

“It was a bad one,” Compton said. “It’s a real densely populated area of town.”

Attackers detonated a second roadside bomb later Sunday as a U.S. convoy was traveling near Fallujah, about 35 miles west of Baghdad, killing an American soldier and wounding three others.

Also Sunday, officials said they arrested five Iraqi suspects in Saturday’s suicide bombings in the Shiite Muslim holy city of Karbala, said Lt. Rafal Smilkowski of the Polish regiment that commands a multinational force in south-central Iraq.

Those attacks killed 19 people, including seven coalition soldiers, and wounded more than 170.

Iraq’s most-wanted

Soldiers are still hunting Izzat Ibrahim al-Douri, one of Saddam’s top deputies and now the most wanted man in Iraq. But whether he plays a direct role in the insurgency is unclear and questioned by some.

Iraqis, some local sheiks among them, have told coalition commanders that al-Douri is not a key player, that he is powerless without Saddam and that he doesn’t command the same rallying influence that the deposed Iraqi president did. Others suggest that he’s seriously ill.

Still there’s a $10 million bounty for his capture and U.S. officers are keen to have him in custody and find out what he knows.

Another sign that military raids are having an impact on the top tier of the insurgency is that many have been caught on the run, hiding out in derelict buildings or even trying to flee through fields.