Pakistani tribal villagers and local people participate in a rally to condemn U.S. drone attacks near President House in Islamabad, capital of Pakistan on February 25, 2012. Hundreds of Pakistani tribesmen and their political supporters started a two-day sit-in in Islamabad against the U.S. drone strikes in the tribal regions.

WASHINGTON — Contrary to assurances it has deployed U.S. drones only against known senior leaders of al-Qaida and allied groups, the Obama administration has targeted and killed hundreds of suspected lower-level Afghan, Pakistani and unidentified “other” militants in scores of strikes in Pakistan’s rugged tribal area, classified U.S. intelligence reports show.

The administration has said that strikes by the CIA’s missile-firing Predator and Reaper drones are authorized only against “specific senior operational leaders of al-Qaida and associated forces” involved in the Sept. 11, 2001, terror attacks who are plotting “imminent” violent attacks on Americans.

“It has to be a threat that is serious and not speculative,” President Barack Obama said in a Sept. 6, 2012, interview with CNN. “It has to be a situation in which we can’t capture the individual before they move forward on some sort of operational plot against the United States.”

Copies of the top-secret U.S. intelligence reports reviewed by McClatchy, however, show that drone strikes in Pakistan over a four-year period didn’t adhere to those standards.

The intelligence reports list killings of alleged Afghan insurgents whose organization wasn’t on the U.S. list of terrorist groups at the time of the 9/11 strikes; of suspected members of a Pakistani extremist group that didn’t exist at the time of 9/11; and of unidentified individuals described as “other militants” and “foreign fighters.”

In a response to questions from McClatchy, the White House defended its targeting policies, pointing to previous public statements by senior administration officials that the missile strikes are aimed at al-Qaida and associated forces.

Micah Zenko, an expert with the Council on Foreign Relations, a bipartisan foreign policy think tank, who closely follows the target killing program, said McClatchy’s findings indicate that the administration is “misleading the public about the scope of who can legitimately be targeted.”

The documents also show that drone operators weren’t always certain who they were killing despite the administration’s guarantees of the accuracy of the CIA’s targeting intelligence and its assertions that civilian casualties have been “exceedingly rare.”

McClatchy’s review is the first independent evaluation of internal U.S. intelligence accounting of drone attacks since the Bush administration launched America’s secret aerial warfare on Oct. 7, 2001, the day a missile-carrying Predator took off for Afghanistan from an airfield in Pakistan on the first operational flight of an armed U.S. drone.

The analysis takes on additional significance because of the domestic and international debate over the legality of drone strikes in Pakistan amid reports that the administration is planning to broaden its use of targeted killings in Afghanistan and North Africa.

The U.S. intelligence reports reviewed by McClatchy covered most — although not all — of the drone strikes in 2006-2008 and 2010-2011.In that later period, Obama oversaw a surge in drone operations against suspected Islamist sanctuaries on Pakistan’s side of the border that coincided with his buildup of 33,000 additional U.S. troops in southern Afghanistan. Several documents listed casualty estimates as well as the identities of targeted groups.

McClatchy’s review found that:

— At least 265 of up to 482 people who the U.S. intelligence reports estimated the CIA killed during a 12-month period ending in September 2011 were not senior al-Qaida leaders but instead were “assessed” as Afghan, Pakistani and unknown extremists. Drones killed only six top al Qaida leaders in those months, according to news media accounts.

Forty-three of 95 drone strikes reviewed for that period hit groups other than al-Qaida, including the Haqqani network, several Pakistani Taliban factions and the unidentified individuals described only as “foreign fighters” and “other militants.”

During the same period, the reports estimated there was a single civilian casualty, an individual killed in an April 22, 2011, strike in North Waziristan, the main sanctuary for militant groups in Pakistan’s tribal areas.

— At other times, the CIA killed people who only were suspected, associated with, or who probably belonged to militant groups.

To date, the Obama administration has not disclosed the secret legal opinions and the detailed procedures buttressing drone killings, and it has never acknowledged the use of so-called “signature strikes,” in which unidentified individuals are killed after surveillance shows behavior the U.S. government associates with terrorists, such as visiting compounds linked to al-Qaida leaders or carrying weapons. Nor has it disclosed an explicit list of al Qaida’s “associated forces” beyond the Afghan Taliban.

The little that is known about the opinions comes from a leaked Justice Department white paper, a half-dozen or so speeches, some public comments by Obama and several top lieutenants, and limited open testimony before Congress.

“The United States has gone far beyond what the U.S. public — and perhaps even Congress — understands the government has been doing and claiming they have a legal right to do,” said Mary Ellen O’Connell, a Notre Dame Law School professor who contends that CIA drone operations in Pakistan violate international law.

The documents McClatchy has reviewed do not reflect the entirety of the killings associated with U.S. drone attacks in Pakistan, which independent reports estimate at between 1,990 and 3,581.

But the classified reports provide a view into how drone strikes were carried out during the most intense periods of drone warfare in Pakistan’s remote tribal area bordering Afghanistan. Specifically, the documents reveal estimates of deaths and injuries; locations of militant bases and compounds; the identities of some of those targeted or killed; the movements of targets from village to village or compound to compound; and, to a limited degree, the rationale for unleashing missiles.

The documents also reveal a breadth of targeting that is complicated by the culture in the restive region of Pakistan where militants and ordinary tribesmen dress the same, and carrying a weapon is part of the centuries-old tradition of the Pashtun ethnic group.

The Haqqani network, for example, cooperates closely with al-Qaida for philosophical and tactical reasons, and it is blamed for some of the bloodiest attacks against civilians and U.S.-led forces in Afghanistan. But the Haqqani network wasn’t on the U.S. list of international terrorist groups at the time of the strikes covered by the U.S. intelligence reports, and it isn’t known to ever have been directly implicated in a plot against the U.S. homeland.

Other groups the documents said were targeted have parochial objectives: the Pakistani Taliban seeks to topple the Islamabad government; Lashkar i Jhangvi, or Army of Jhangvi, are outlawed Sunni Muslim terrorists who’ve slaughtered scores of Pakistan’s minority Shiites and were blamed for a series of attacks in Pakistan and Afghanistan, including a 2006 bombing against the U.S. consulate in Karachi that killed a U.S. diplomat. Both groups are close to al-Qaida, but neither is known to have initiated attacks on the U.S. homeland.

“I have never seen nor am I not aware of any rules of engagement that have been made public that govern the conduct of drone operations in Pakistan, or the identification of individuals and groups other than al-Qaida and the Afghan Taliban,” said Christopher Swift, a national security law expert who teaches national security affairs at Georgetown University and closely follows the targeted killing issue. “We are doing this on a case-by-case, ad hoc basis, rather than a systematic or strategic basis.”

The administration has declined to reveal other details of the program, such as the intelligence used to select targets and how much evidence is required for an individual to be placed on a CIA “kill list.” The administration also hasn’t even acknowledged the existence of so-called signature strikes, let alone discussed the legal and procedural foundations of the attacks.

Leaders of the Senate and House intelligence committees say they maintain robust oversight over the program. Senate Intelligence Committee Chairwoman Diane Feinstein, D-Calif., disclosed in a Feb. 13 statement that the panel is notified “with key details . . . shortly after” every drone strike. It also reviews videos of strikes and considers “their effectiveness as a counterterrorism tool, verifying the care taken to avoid deaths to non-combatants and understanding the intelligence collection and analysis that underpins these operations.”

But until last month, Obama had rebuffed lawmakers’ repeated requests to see all of the classified Justice Department legal opinions on the program, giving them access to only two dealing with the president’s powers to order targeted killings. It then allowed the Senate committee access to all opinions pertaining to the killing of U.S. citizens to clear the way for the panel’s March 7 confirmation of John Brennan, the former White House counterterrorism chief and the key architect of the targeted killings program, as the new CIA director. But it continues to deny access to other opinions on the grounds that they are privileged legal advice to the president.

Moreover, most of the debate in the United States has focused on the deaths of four Americans — all killed in drone strikes in Yemen, but only one intentionally targeted — and not the thousands of others who’ve been killed, the majority of whom have been hit in Pakistan.

Obama and his top aides say the United States is in an “armed conflict” with al-Qaida and the Afghan Taliban, and the targeted killing program complies with U.S. and international laws, including an “inherent” right to self-defense and the international laws of war. Obama also derives his authority to order targeted killings from the Constitution and a Sept. 14, 2001, congressional resolution empowering the president to use “all necessary and appropriate force” against those who perpetrated 9/11 and those who aided them, they say.

Time and again, the administration has defined the drone targets as operational leaders of al-Qaida, the Afghan Taliban and associated groups plotting imminent attacks on the American homeland. Occasionally, however, officials have made oblique references to undefined associated forces and threats against unidentified Americans and U.S. facilities.

On April 30, 2012, Brennan gave the most detailed explanation of Obama’s drone program. He referred to al-Qaida 73 times, the Afghan Taliban three times and mentioned no other group by name.

“We only authorize a particular operation against a specific individual if we have a high degree of confidence that the individual being targeted is indeed the terrorist we are pursuing,” Brennan said.

To be sure, America’s drone program has killed militants without risk to the nation’s armed forces.

The administration argues that drones — in Brennan’s words — are a “wise choice” for fighting terrorists. Over the years, the aircraft have battered al-Qaida’s Pakistan-based core leadership and crippled its ability to stage complex attacks. And officials note it has been done without sending U.S. troops into hostile territory or causing civilian casualties “except in the rarest of circumstances.”

“Any actions we take fully comport to our law and meet the standards that I think . . . the American people expect of us as far as taking actions we need to protect the American people, but at the same time ensuring that we do everything possible before we need to resort to lethal force,” Brennan said at his Feb. 7 Senate Intelligence Committee confirmation hearing.

Some legal scholars and human rights organizations, however, dispute the program’s legality.

Obama, they think, is misinterpreting international law, including the laws of war, which they say apply only to the uniformed military, not the civilian CIA, and to traditional battlefields like those in Afghanistan, not to Pakistan’s tribal area, even though it may be a sanctuary for al-Qaida and other violent groups. They argue that Obama also is strengthening his executive powers with an excessively broad application of the September 2001 use-of-force resolution.

The administration’s definition of “imminent threat” also is in dispute. The Justice Department’s leaked white paper argues the United States should be able “to act in self-defense in circumstances where there is evidence of further imminent attacks by terrorist groups even if there is no specific evidence of where such an attack will take place or of the precise nature of the attack.” Legal scholars counter that the administration is using an exaggerated definition of imminence that doesn’t exist in international law.

“I’m thankful that my doctors don’t use their (the administration’s) definition of imminence when looking at imminent death. A head cold could be enough to pull the plug on you,” said Morris Davis, a Howard University Law School professor and former Air Force lawyer who served as chief prosecutor of the Guantanamo Bay terrorism trials.

Since 2004, drone program critics say, the strikes have killed hundreds of civilians, fueling anti-U.S. outrage, boosting extremist recruiting, and helping to destabilize Pakistan’s U.S.-backed government. And some experts warn that the United States may be setting a new standard of international conduct that other countries will grasp to justify their own targeted killings and to evade accountability.

Other governments “won’t just emulate U.S. practice but (will adopt) America’s justification for targeted killings,” said Zenko of the Council on Foreign Relations. “When there is such a disconnect between who the administration says it kills and who it (actually) kills, that hypocrisy itself is a very dangerous precedent that other countries will emulate.”

A special U.N. human rights panel began a nine-month investigation in January into whether drone strikes, including the CIA operations in Pakistan, violate international law by causing disproportionate numbers of civilian casualties. The panel’s head, British lawyer Ben Emmerson, declared after a March 11-13 visit to Pakistan that the U.S. drone campaign “involves the use of force on the territory of another state without its consent and is therefore a violation of Pakistan’s sovereignty.”

The administration asserts that drones are used to hit specific individuals only after their names are added to a “list of active terrorists,” following a process of “extraordinary care and thoughtfulness” that confirms their identities as members of al-Qaida or “associated forces” and weighs the strategic value of killing each one.

Yet the U.S. intelligence reports show that 43 out of the 95 strikes recorded in reports for the year ending in September 2011 were launched against groups other than al-Qaida. Prominent among them were the Haqqani network and the Taliban Movement of Pakistan.

The Haqqani network is an Afghan Taliban-allied organization that operates in eastern Afghanistan and whose leaders are based in Pakistan’s adjacent North Waziristan tribal agency. The United States accuses the group of staging some of the deadliest terrorist attacks in Kabul, including on the Indian and U.S. embassies, killing civilians, and attacking U.S.-led forces in Afghanistan. But the Obama administration didn’t officially designate the network as a terrorist group until September 2012.

Its titular head is Jalaluddin Haqqani, an aging former anti-Soviet guerrilla who served as a minor minister and top military commander in the Taliban regime that sheltered al-Qaida until both were driven into Pakistan by the 2001 U.S. intervention in Afghanistan. U.S. officials allege that the group, whose operational chief is Haqqani’s son, Sirajuddin, closely works with al-Qaida and is backed by elements of the Pakistani army-led Inter-Services Intelligence spy service, a charge denied by Islamabad.

At least 15 drone strikes were launched against the Haqqani network or locations where its fighters were present during the one-year period ending in September 2011, according to the U.S. intelligence reports. They estimated that up to 96 people — or about 20 percent of the total for that period — were killed.

One report also makes clear that during the Bush administration, the agency killed Haqqani family women and children.

According to the report, an undisclosed number of Haqqani subcommanders, unnamed Arabs and unnamed “members of the extended Haqqani family” died in a Sept. 8, 2008, strike. News reports on the attack in the North Waziristan village of Dandey Darapakhel said that among as many as 25 dead were an Arab who was chief of al-Qaida’s operations in Pakistan, and eight of Jalaluddin Haqqani’s grandchildren, one of his wives, two nieces and a sister.

The U.S. intelligence reports estimated that as many as 31 people were killed in at least nine strikes on the Pakistani Taliban or on locations that the group shared with others between January 2010 and September 2011. While U.S. officials say the Taliban Movement of Pakistan works closely with al-Qaida, its goal is to topple the Pakistani government through suicide bombings, assaults and assassinations, not attacking the United States. The group wasn’t founded until 2007, and some of the strikes in the U.S. intelligence reports occurred before the administration designated it a terrorist organization in September 2010.

The U.S. intelligence reports estimated that the CIA killed scores of other individuals in 2010 and 2011 in strikes on other non-al-Qaida groups categorized as suspected extremists and unidentified “foreign fighters,” or “other militants.” Some died in what appeared to be signature strikes, their vehicles blown to pieces sometimes only a few days after being monitored visiting the sites of earlier drone attacks, or driving between compounds linked to al Qaida or other groups.

“The first challenge in any war is knowing who you’re fighting, and distinguishing those that pose a credible threat to your interests and security,” said Swift.

The U.S. intelligence documents also describe a lack of precision when it comes to identifying targets.

Consider one attack on Feb. 18, 2010.

Information, according to one U.S. intelligence account, indicated that Badruddin Haqqani, the then-No. 2 leader of the Haqqani network, would be at a relative’s funeral that day in North Waziristan. Watching the video feed from a drone high above the mourners, CIA operators in the United States identified a man they believed could be Badruddin Haqqani from the deference and numerous greetings he received. The man also supervised a private family viewing of the body.

Yet despite a targeting process that the administration says meets “the highest possible standards,” it wasn’t Badruddin Haqqani who died when one of the drone’s missiles ripped apart the target’s car after he’d left the funeral.

It was his younger brother, Mohammad.

Friends later told reporters that Mohammad Haqqani was a religious student in his 20s uninvolved in terrorism; the U.S. intelligence report called him an active member — but not a leader — of the Haqqani network. At least one other unidentified occupant of his vehicle perished, according to the report.

It took the CIA another 18 months to find and kill Badruddin Haqqani.