Despite what a top U.S. military commander describes as "very challenging" situations in Iraqi insurgent strongholds like Fallujah and Najaf, the Pentagon is denying that security conditions in Iraq are spiraling out of control.

Defense Secretary Donald Rumsfeld says "we'll never know" when asked if a bigger U.S. military force inserted into Iraq over a year ago could have prevented situations like the current stand-off with insurgents in Fallujah.

Speaking to reporters at the Pentagon, Mr. Rumsfeld acknowledges commanders have always faced a dilemma in deciding how many troops they need. Too few, he says, and they risk their soldiers' lives. Too many, he said, and the larger American presence would not only require more logistics support but could also alienate more Iraqis. "A larger presence requiring larger support, requiring larger force protection, requiring some way of avoiding being seen as flooding the country with people and becoming clearly an occupying force and just smothering what's going on," he said.

Mr. Rumsfeld defended efforts to negotiate peaceful settlements to the stand-offs between coalition forces and insurgents in Fallujah and Najaf.

He said dialogue is "worth the try", a view supported by General Richard Myers, Chairman of the U.S. military's Joint Chiefs of Staff. "We have dialogue with many Iraqis on this particular issue and I think part of it is having been seen as trying to attempt to do this [resolve stand-offs] in ways that don't alienate the Iraqi people," he said.

But both General Myers and Defense Secretary Rumsfeld insist the insurgents will not be allowed to terrorize Iraqis.