When U.S. forces launched two strikes on alleged Fallujah safehouses of Jordanian-born terrorist Abu Musab al-Zarqawi (search), they relied on significant human intelligence to identify their targets, senior defense officials told Fox News.

Pentagon officials said they haven't yet been given any data on who was killed in the raids on Saturday and Wednesday, or what might have been found in both locations after exploitation teams were sent in to survey the damage. But Zarqawi is not believed to have been killed, the officials said.

Senior defense officials continued to talk up the value of the intelligence that led to the strikes. One official told Fox News that much of the information was of the 'human' intelligence variety, coming from both U.S. and Iraqi sources.

Fallujah is seen as being a haven for Zarqawi and his allies, although senior officials said they don't know if Zarqawi himself is there now.  

Officials also believe the city is a safe haven for other foreign fighters, secular Sunnis, former Baathists and Saddam loyalists. Each group, despite their disparate interests, is aiding the other, they say, creating a well-controlled terror network that is coordinating action not only in the Fallujah area but also in other hotspots like Baghdad.

In an audio tape released by Zarqawi on Wednesday, the terrorist refutes reports made by the U.S.-led coalition that he operates from Fallujah.

"The American strikes at Fallujah are being carried out based on their allegation that I am in Fallujah -- these are lies," Zarqawi said, according to a translation. "They do not know that I am able to move in Iraq freely as a guest."

The name Izzat Ibramhim al Douri (search) came up Wednesday as this terror network was discussed.

Al Douri, the highest-ranking of the coalition's most-wanted 55 Iraqis still at large, was the deputy chairman of Saddam Hussein's Revolutionary Command Council (search), and was cited for several months as the most capable and dangerous Baathist for his ability to coordinate, plan and finance attacks, as well as his ability to recruit fresh insurgents.

Al Douri had fallen off the radar screen as coalition and media focus has shifted to Zarqawi and his ilk, but now senior officials are telling Fox News that al Douri — whom they describe as an avowed and "fanatic" Islamist whose two sons have sworn 'fealty' to Usama bin Laden — is in league with Zarqawi and Al Qaeda elements. Fallujah is the center of their universe, officials said.

Fallujah, being the significant, dangerous, urban area that it is, is still being patrolled by the Fallujah Brigade (search) -- a force of several thousand Iraqis charged with maintaining order there.

One senior official told Fox News that the growing frustration with the Fallujah Brigade's effectiveness is "coming from the Iraqi side, and we're hearing about it."

But another described the long-range Fallujah strategy as a "slow squeeze" on the many dangerous elements in the city, saying politics and public perception are keeping U.S. forces from heading back into the city to clean it out.

Citing Arab media reports of the situation inside the city when U.S. Marines were engaged in action there — a time, the official said, when the rate of bomb attacks in the rest of Iraq was significantly decreased — the official said "we blinked."

Now, he said, the strategy is to wait all of them out.

Fox News' Bret Baier and Ian McCaleb contributed to this report.