Political turmoil and a spate of brazen attacks by Taliban fighters are forcing Pakistan’s president to scale back his government’s pursuit of al-Qaeda, according to US intelligence officials who fear that the terrorist network will be able to accelerate its efforts to rebuild and plot new attacks. The development threatens a pillar of US counter-terrorism strategy, which has depended on Pakistan to play a lead role in keeping al-Qaeda under pressure to reduce its ability to coordinate strikes. President Pervez Musharraf, facing a potentially fateful election next month and confronting calls to yield power after years of autocratic rule, appears too vulnerable to pursue aggressive counter-terrorism operations at the behest of the United States, the intelligence officials said. At the same time, the Pakistani military has suffered a series of embarrassing setbacks at the hands of militants in tribal areas bordering Afghanistan where Osama bin Laden and other al-Qaeda figures are believed to be hiding.US intelligence officials said the conditions that have allowed al-Qaeda to regain strength are likely to persist, enabling it to continue training foreign fighters and plot new attacks. “We are worried,” said a senior US counter-terrorism official who closely monitors Pakistan’s pursuit of al-Qaeda in the rugged frontier region.