The U.S. military has completed an overall assessment of the two-week-old anti-insurgent operation in Fallujah, and the results are stunning.
U.S. troops and their Iraqi allies found no fewer than 653 improvised explosive devices, or IEDs, during their sweep through the Iraqi city, according to a copy of the assessment obtained by ABC News. IEDs are the bombs used by Iraqi insurgents to kill coalition and Iraqi personnel and civilians.
Eleven IED factories were uncovered, with cell phones for detonators and hand-held radios and receivers.
There was a weapons cache found on one out of every five blocks, the U.S. assessment says, and in 60 of the city's 100 mosques, U.S. Marines found weapons or fighters inside.
Military officers say there were enough weapons uncovered in Fallujah to fuel a nationwide rebellion.
"It was even more of a safe haven than I think we realized," said Jack Keane, an ABC News consultant and former vice chief of staff of the Army. "Weapons, supplies that were in that city exceed anything we expected."
A senior military official in Baghdad told ABC News today that he is "cautiously optimistic" that the assault on Fallujah may have made a real dent in the insurgency. Attacks in the Baghdad area have been significantly reduced since the invasion -- nearly cut in half.
The United States is keeping up the pressure. Thousands of U.S., British and Iraqi forces continue to target nearly a dozen towns south of Baghdad in what is called the "triangle of death," a rural area where troops are targeting insurgents who may have fled Fallujah, or those who may be helping them.
The same is happening in Mosul in the north. Over the last month, forces have killed or captured more than 100 enemy fighters. That's one reason why U.S. commanders think the insurgents are taking the fight directly to the Iraqis instead.
One more thing the Marines found in Fallujah was evidence of atrocities -- houses where hostages were kept and many times killed, as well as video of four people being beheaded..
The key phrase about the effect of the Fallujah operation is "cautiously optimistic" -- there is still fear that the insurgents are merely regrouping for a new wave of attacks.
ABC News' Martha Raddatz and Brian Hartman reported this story for World News Tonight.