They were among at least eight senior Al Qaeda figures reportedly killed in Predator strikes over the last seven months as part of a stepped-up missile campaign.
Bruce Hoffman, a terrorism expert at Georgetown University, said Feinstein's comments put Pakistan's government on the spot.
"If accurate, what this says is that Pakistani involvement, or at least acquiescence, has been much more extensive than has previously been known," he said. "It puts the Pakistani government in a far more difficult position [in terms of] its credibility with its own people. Unfortunately it also has the potential to threaten Pakistani-American relations."
As chairwoman of the Senate Intelligence Committee, Feinstein is privy to classified details of U.S. counter-terrorism efforts. The CIA does not publicly acknowledge a campaign against Pakistan-based extremists using remotely piloted planes, making Feinstein's comment all the more unusual.
Feinstein's disclosure came during testimony before the Senate Intelligence Committee by U.S. Director of National Intelligence Dennis C. Blair on the nation's security threats. Blair did not respond directly to Feinstein's remark, except to say that Pakistan was "sorting out" its cooperation with the United States.
Pakistani officials have long denied that they have even granted the U.S. permission to fly the Predator planes over Pakistani territory, let alone to operate the aircraft from within the country.
The civilian leadership that took over from an unpopular former general, Pervez Musharraf, last year, has gone to significant lengths to distance itself from the Predator strikes.
The Pakistani government regularly lodges diplomatic protests against the strikes as a violation of its sovereignty, and officials said the subject was raised with Richard C. Holbrooke, a newly appointed U.S. envoy to the region, who completed his first visit to the country Thursday.
But a former CIA official familiar with the Predator operations said Pakistan's government secretly approves of the flights because of the growing militant threat.
Feinstein prefaced her comment about the Predator basing Thursday by noting that Holbrooke "ran into considerable concern about the use of the Predator strikes in the FATA areas," a reference to what Pakistan calls its Federally Administered Tribal Area along the border with Afghanistan.
Many Pakistanis believe that the civilian leadership, despite public anger, has continued Musharraf's policy of giving the United States tacit permission to carry out the strikes.
The CIA has been working to step up its presence in Pakistan in recent years. It has deployed as many as 200 people to the country, one of its largest overseas operations besides Iraq, current and former agency officials have estimated. That contingent works alongside other U.S. operatives who specialize in electronic communications and spy satellites.
In his prepared testimony Thursday, Blair said that Al Qaeda had "lost significant parts of its command structure since 2008."
--
greg.miller@latimes.com
--
Times staff writer Laura King in Istanbul, Turkey, contributed to this report.
