The Pentagon has found that Iraqi insurgents can conduct up to 60 strikes a day and occasionally more, the chairman of the U.S. Joint Chiefs of Staff said on Thursday. "We've tracked the number of attacks per day and what they can do is 50 to 60 attacks that they are able to conduct countrywide, with spikes. And that seems to be their capacity," Air Force Gen. Richard Myers told the Senate Armed Services Committee. Myers, who testified with Defense Secretary Donald Rumsfeld, characterized the insurgency fighting some 150,000 U.S. forces in Iraq as "a limited capacity." He said it was difficult to determine the number of insurgents in Iraq because "they don't have a central organization ... so as you pick up insurgents and you debrief them and you find what they have in their rooms and on their computers, you don't find the wiring diagram." Rumsfeld on Wednesday told a House of Representatives committee he did not "have a lot of confidence" in the CIA and Defense Intelligence Agency estimates on the number of insurgents, which are classified. --More 0119 Local Time 2219 GMT