WASHINGTON, April 30: Bush administration officials are expressing increasing alarm that a deal being negotiated between the new Pakistani Government and militant tribes in the country’s unruly border area will lead to further unraveling of security in the region.

Cross-border attacks into Afghanistan by militants based in Pakistan doubled in March from the same period a year ago and have not diminished in April, a Western military official said, while Pakistani counter-insurgency operations in the tribal areas have dropped sharply during the talks.

American counterterrorism officials express concern that the new coalition government in Islamabad may withdraw some of the 120,000 Pakistani troops in the border area or curtail flights by the Central Intelligence Agency’s armed Predator aircraft in the region.

Indeed, Washington and Islamabad seem to be on dueling timetables, with the Bush administration trying to cripple al-Qaeda’s safe havens before leaving office, and the new Pakistani government seeking to establish credibility with its public by distancing itself from the American-backed policies of President Pervez Musharraf.

American officials say that Washington’s options now are even more limited, in part because Musharraf is no longer calling the shots, and that the situation in the tribal areas is unlikely to improve significantly before President Bush leaves office. American economic and development aid aimed to help wean the region off the militants’ influence is just now seeping into the tribal areas, while a tribal paramilitary force still needs years of training and equipping to be an effective counterinsurgency unit.

The problems confronting the administration reflect what critics say is a failure over the past several years to pay sufficient attention to the growing numbers of Qaeda and Taliban fighters drawn to safe havens in the tribal area. Even under Musharraf, the administration’s main ally in Pakistan, the United States failed to develop a governmentwide plan to combat the militancy in the turbulent borderlands, these critics say.

The leaders of Pakistan’s new government, Asif Ali Zardari of the Pakistan Peoples Party and Nawaz Sharif of the Pakistan Muslim League-N, have vowed to honor their campaign pledges to break with Musharraf’s emphasis on using military force in the tribal areas, a practice critics say has been heavy-handed and has undercut the government’s goals.

The government has begun a negotiating strategy that officials hope will win over those in the tribal areas who in recent years have been caught up in a wave of anti-American sentiment and, in some cases, who are actively helping al-Qaeda.

American policymakers, diplomats and senior military officers voice fears that a new agreement, like past accords brokered with the militants by Musharraf, would allow al-Qaeda and the Taliban to regroup, rearm and plot new attacks in Pakistan, Afghanistan, Europe and the United States. American defence officials and independent analysts estimate between 150 and 500 hard-core Qaeda fighters are operating in the tribal areas.

But administration officials concede they have limited leverage with Pakistan’s new Government and, for now, may have to allow the talks to play out and then press the Government to enforce any deals.