Saddam Hussein's most trusted paramilitary militia, Saddam's Fedayeen, has assassinated the Iraqi leader's enemies, put down protests and ruthlessly cracked down on dissidents since its founding in 1995.

Now, with U.S.-led coalition troops advancing toward Baghdad, Saddam's Fedayeen -- whose name means "those ready to sacrifice themselves for Saddam" -- are putting up stiff resistance and trying to prevent regular army soldiers from surrendering.

Reports from the front suggest Fedayeen members may have organized battlefield ruses, like posing as civilians or faking surrender, to trap U.S. and British forces. Such scenes played out in An Nasiriyah and Umm Qasr, where the advancing troops suffered their first major casualties.

The result of the Fedayeen activity, intended or not, is to sow suspicion and division between the invading troops and the civilians and stop any uprising against Saddam.

U.S. intelligence believes the Fedayeen were dispatched from their strongholds in the Baghdad area to outlying areas over the last few weeks.

Gen. Tommy Franks, speaking Monday in Qatar, said U.S. forces had "intentionally bypassed enemy formations," and the Fedayeen had been harassing the U.S. rear in southern Iraq.

"We know that the Fedayeen has in fact put himself in a position to mill about, to create difficulties in rural areas," Franks said. "I can assure you that contact with those forces is not unexpected."

The guerrillas were formed to quash internal dissent and disturbances after Iraq's defeat in the 1991 Gulf War, especially in the oppressed Shiite Muslim areas in central and southern Iraq. The first recruits -- all extremely loyal to the ruling Baath party -- included criminals who were pardoned in exchange for serving in the units.

Prewar U.S. intelligence estimates put the Fedayeen's strength at between 20,000 and 25,000 fighters. Other analysts estimate the force could number 40,000, broken into brigades of 3,000 each. Training includes urban warfare and suicide missions. One of their endurance drills is to survive on snakes and dog meat.

They dress in black uniforms and cover their faces with black scarves to instill fear, although they also have been known to operate in civilian clothes.

Ali Abdel Amir, an Iraqi journalist operating in neighboring Jordan, said Saddam trusts the force even more than his elite Republican Guard.

"They have blind loyalty, they might even kill their fathers if they are ordered to do so," he told The Associated Press from Amman.

Fedayeen members receive up to $100 a month, compared with the $3 government employees are paid each month. They receive plots of land and other privileges, such as extra food rations and free medical care.

The Fedayeen report directly to Saddam's eldest son, Odai, a powerful figure in Iraq with a reputation for extravagance and violence.

In 1998, Fedayeen members swept the Shiite city of Karbala looking for would-be assassins of Izzat Ibrahim, Saddam's deputy on the Revolution Command Council, Iraq's highest executive body. Ibrahim survived, and hundreds of people were arrested in the sweeps.

In 1999, the Fedayeen were responsible for a crackdown on Shiites in a Baghdad suburb who were protesting the assassination of Grand Ayatollah Mohammed Sadeq al-Sadr, a leading Iraqi Shiite cleric, and his two sons in the holy city of Najaf. Dozens of people were killed in the operation.

This month, Al Zawra, a weekly newspaper owned by Odai, reported that Fedayeen units were sent to the southern town of Al-Majar to crush a protest by villagers. They reportedly destroyed three houses and took the families into custody.

Earlier this month, U.S. officials claimed Fedayeen members were acquiring military uniforms "identical down to the last detail" to those worn by American and British forces and planned to use them to shift blame for atrocities.

But U.S. officials before the war also described the Fedayeen as a lightly armed militia capable of combating internal unrest, and suggested other security and military forces, such as the Republican Guard and its paramilitary counterpart, the Special Republican Guard, would pose a greater threat to U.S. troops.

"They are a little nuisance that can make some trouble, but not hinder the advance of the troops," said Mohammed Qadri Saeed, a military analyst at the Cairo-based Al Ahram Center for Strategic Studies.