The White House has started conditioning the award of billions of dollars in security assistance to Pakistan on whether Islamabad shows progress on a secret scorecard of U.S. objectives to combat al Qaeda and its militant allies. The U.S. also is asking Pakistan to take specific steps to ease bilateral tensions.

The classified system, put in place after the U.S. raid that killed al Qaeda leader Osama bin Laden at his Pakistani hideout, signals a shift by the White House toward a pay-for-performance relationship with Pakistan, as doubts grow that the two countries can for now forge a broader alliance based on shared interests.

A senior military official called the unusual new approach "a hard-knuckled reflection of where we are right now" in relations. U.S. officials cited the sharp breakdown in counterterrorism cooperation that followed the bin Laden raid in May and the arrest of a Central Intelligence Agency contractor in Pakistan this year.

The new approach represents an effort to salvage as much counterterrorism cooperation as the Obama administration can at a time when top U.S. officials believe themselves in a race against time to deal a deathblow to al Qaeda's remaining leadership in Pakistan.

Since 2001, the U.S. has lurched from one policy to another in an attempt to win Pakistan's help in fighting al Qaeda and its allies, only to find itself frustrated by what the U.S. sees as Islamabad's double-game in accepting American aid more than $20 billion since the 9/11 attacks—while still providing clandestine support to some of America's enemies.

U.S. aid to Pakistan, including economic and security-related assistance, totaled nearly $4.5 billion in fiscal 2010. Security aid accounted for more than $2.7 billion of that, according to the Congressional Research Service.

Officials say the White House has already frozen some $800 million in security assistance to Pakistan in recent months because of factors that include Islamabad's refusal to readmit American trainers and military personnel who process Pakistani reimbursement claims items that fall into categories on the U.S. performance checklist.

The system isn't hard and fast reflecting the volatile nature of the relationship, U.S. officials said. Total aid spending for this fiscal year isn't yet available—security aid is expected to total around $2.5 billion, congressional officials say—and the final amount that may be withheld will depend on the level of Pakistani cooperation and how aggressive the White House decides to be in withholding funds.

The White House is responding in part to mounting calls in Congress for putting stringent new conditions on future aid to Pakistan, officials say. Many lawmakers have demanded sharp cuts in military assistance. They say the discovery that bin Laden had been living so close to the Pakistani capital for years fueled the U.S. belief that al Qaeda and other anti-American militant groups have received secret protection or support from elements within the country's military-intelligence agencies.

"The message is: You make progress in these areas, and we can release some of this assistance," a senior U.S. official said of the review process. "Give us something that we can show [Congress] that we're working together."

Under the new approach, the office of the Director of National Intelligence James Clapper is compiling classified scorecards that track Pakistan's cooperation in four areas, referred to in the White House as "baskets."

Each basket contains a to-do list that the administration wants from Pakistan.

Washington has told Islamabad that future payouts of security assistance would hinge on Pakistan showing it is making progress in these four areas, U.S. officials said. The White House hasn't assigned specific dollar values to each item.

U.S. officials say the Obama administration presented the request list to Pakistani officials in May, shortly after the bin Laden raid. The raid, carried out without Pakistani knowledge, had already fueled Pakistani concerns that the U.S. doesn't consider Islamabad an equal partner.

A spokesman for Pakistan's Inter-Services Intelligence agency denied the U.S. had formally presented Pakistan with such a list and said it was Pakistan's prerogative to decide how to combat terrorism and conduct relations with Afghanistan.

Underscoring internal tensions that Islamabad faces, a bomb destroyed a hotel in the country's southwestern Baluchistan province Sunday, killing 12 people, authorities said.

Pakistan's Ambassador to the U.S., Husain Haqqani, said the relationship between Islamabad and Washington was more than a set of quid-pro-quo transactions. "This relationship is not just about aid," he said.

"When it comes to our military aid, we are not prepared to continue providing that at the pace we were providing it unless and until we see certain steps taken," a senior U.S. official said. "We have identified a number of areas in which both Pakistan and the U.S. need to take measures together to move our relationship forward. And while the areas where we need to make progress are not secret, we are discussing them privately, not publicly."

Advocates of the system say it is the only viable approach at this time. Others are critical.

"Part of it sounds paternalistic and arrogant," said Henry Crumpton, a former senior Central Intelligence Agency and State Department counterterrorism official. "It's as if you're giving a report card to a child. Instead, you [should] have a joint strategy, with an ally, and you find operations that support that strategy, and you measure progress jointly."

The four baskets are: Pakistani cooperation in exploiting the bin Laden compound; Pakistani cooperation with the war in Afghanistan; Pakistani cooperation with the U.S. in conducting joint counterterrorism operations; and cooperation in improving the overall tone in bilateral relations. Officials said the details of those baskets were classified.

Officials say Islamabad has largely complied with the main items in the first basket by returning the tail section of the helicopter that crashed in the bin Laden raid and by allowing U.S. interrogations of bin Laden's family in Pakistani custody.

But the return of the tail section—three weeks after the raid—remains a contentious issue. U.S. officials have information that suggests Pakistani officials allowed the Chinese to examine the tail rudder of the stealth helicopter before returning it. However, the information isn't conclusive. U.S. officials had asked the Pakistanis not to allow anyone else access to the helicopter.

Pakistan has also made progress toward engaging the government of Afghan President Hamid Karzai, citing a series of recent bilateral meetings, U.S. officials say. The U.S. wants Pakistan, however, to do more to stop the flow of fighters and explosives across its border into Afghanistan.

Officials see less progress in other areas. The U.S. wants Pakistan to authorize joint operations against al Qaeda leaders and to free a detained Pakistani doctor who helped the CIA track bin Laden. The basket that measures progress in improving the overall tone in bilateral relations includes a specific call on Pakistan to renew visas for U.S. government personnel to work in Pakistan. The CIA and the military say Pakistan has been holding back hundreds of visa requests.

Mr. Clapper's office looks at each item in each basket and assigns "green light," "yellow light" and "red light" assessments to show whether progress is being made.

According to officials, the classified score cards are presented to the so-called deputies committee of the White House National Security Council. The deputies, who represent senior members of the president's cabinet, oversee the review process and the release of security funding. Officials wouldn't say how they decide how much money to release for incremental progress by Pakistan.

While U.S. security assistance to Pakistan—such as military equipment, training and reimbursement for Pakistani military operations against militants—has been tied to progress completing items on the U.S. checklist, U.S. civilian economic and development aid to Pakistan isn't affected, U.S. officials said.

Some current and former officials say the approach shows that the goal of establishing a broad strategic partnership with Pakistan is losing support within the U.S. government.

The chairman of the U.S. military's Joint Chiefs of Staff, Adm. Mike Mullen, and the late U.S. special envoy to Pakistan and Afghanistan, Richard Holbrooke, championed the strategic partnership approach with Pakistan starting in 2009 in the belief that Islamabad would be more cooperative if it believed the U.S. was committed to a long-term relationship.

Adm. Mullen is due to step down as chairman in September, and several officials said doubts about the approach have grown within the White House and the intelligence community.

A military official said: "It's still the military's intention to continue to try to pursue a strategic partnership with the Pakistani military. We recognize where we are in the relationship and that it is very tough right now, but nothing has changed about our long term goals of better cooperation."