NEW YORK - A senior US lawmaker says that unmanned CIA Predator aircraft operating in Pakistan are flown from an air base inside that country. The disclosure by Senator Dianne Feinstein, a Democrat who heads the Senate Intelligence Committee, is likely to embarrass the Pakistani government and complicate its counterterrorism collaboration with the United States, according to a dispatch in The Los Angles Times Friday. Sen Feinstein's revelation is the first ever in which a US official had publicly commented on where the Predator aircraft patrolling Pakistan take off and land. At a congressional hearing on Thursday, she expressed surprise at Pakistani opposition to the ongoing campaign of Predator-launched CIA missile strikes against extremist targets along Pakistan's border with Afghanistan. "As I understand it, these are flown out of a Pakistani base," she said. "The basing of the pilotless aircraft in Pakistan suggests a much deeper relationship with the United States on counterterrorism matters than has been publicly acknowledged," the newspaper said. "Such an arrangement would be at odds with protests lodged by officials in Islamabad and could inflame anti-American sentiment in the country". The CIA declined to comment, but former US intelligence officials, speaking on condition of anonymity because of the sensitivity of the information, confirmed to The Times that Feinstein's account was accurate. Philip LaVelle, a spokesman for Ms Feinstein, said her comment was based solely on previous news reports that Predators were operated from bases near Islamabad. "We strongly object to Sen Feinstein's remarks being characterised as anything other than a reference" to an article that appeared last March in the Washington Post, LaVelle said. Feinstein did not refer to newspaper accounts during the hearing. Many counterterrorism experts have assumed that the aircraft take off from US military installations in Afghanistan and are remotely piloted from locations in the United States, The Times said. Experts said the disclosure could create political problems for the government in Islamabad, which is considered relatively weak. Bruce Hoffman, a terrorism expert at Georgetown University, was quoted as saying that Ms 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 US counterterrorism efforts. The CIA does not publicly acknowledge a campaign against Pakistan-based extremists using remotely piloted planes, making Ms Feinstein's comment all the more unusual. Ms Feinstein's disclosure came during testimony before the Senate Intelligence Committee by US Director of National Intelligence Dennis Blair on the nation's security threats. Blair did not respond directly to Ms Feinstein's remark, except to say that Pakistan was "sorting out" its cooperation with the United States. But one former CIA official familiar with the Predator operations said Pakistan's government secretly approves of the flights because of the growing militant threat inside the country, according to the newspaper. Ms Feinstein prefaced her comment about the Predator basing Thursday by noting that US envoy Richard Holbrooke "ran into considerable concern about the use of the Predator strikes in the FATA areas." "Despite public anger, many Pakistanis believe the civilian leadership has continued Musharraf's policy of giving the United States tacit permission to carry out the strikes, The Times said. 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, the newspaper said, citing current and former agency officials. That contingent works alongside other US operatives who specialise 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."