AlQaeda's leaders were increasingly worried about spies in their midst, drones in the air and secret tracking devices reporting their movements as the U.S.-led war against them ground on,documentsseized in the 2011 raid on OsamabinLaden's Pakistani hideout and reviewed by Reuters reveal.

The cache of 113documents, translated and declassified by U.S. intelligence agencies, are mostly dated between 2009 and 2011, intelligence officials said.

Thedocuments- the second tranche from the raid to have been declassified since May 2015 - depict analQaedathat was unwavering in its commitment to globaljihad, but with its core leadership in Pakistan and Afghanistan under pressure on multiple fronts.

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U.S. President Barack Obama has said drone strikes and other counter-terrorism operations depletedalQaeda's originalleadership, culminating inbinLaden's killing by U.S. Navy SEALs on May 2, 2011. In the years since, the organization has proved resilient from Afghanistan to North Africa, and its ideologicalrival, Islamic State, has grown and spread.

In one document,binLadenissues instructions toalQaedamembers holding an Afghan hostage to be wary of possible tracking technology attached to the ransom payment.

"It is important to get rid of the suitcase in which the funds are delivered, due to the possibility of it having a tracking chip in it,"binLadenstates in a letter to an aide identified only as "Shaykh Mahmud."

In an apparent reference to armed U.S. drones patrolling the skies,binLadensays his negotiators should not leave their rented house in the Pakistani city of Peshawar "except on a cloudy overcast day."

While the document is undated, the hostage, Afghan diplomat Abdul Khaliq Farahi, was held from September 2008 to late 2010.

Another, fragmentary document acknowledges thatalQaedaexecuted four would-be volunteers on suspicion of spying, only to discover they were probably innocent, according to senior U.S. intelligence officials authorized to discuss the materials in advance of their public release.

"I did not mention this to justify what has happened," wrote the undated letter's unidentified author, adding, "we are in an intelligence battle and humans are humans and no one is infallible."

In a May 11, 2010 letter to his then second-in-command, Atiyah AbdalRahman,binLadenurged caution in arranging an interview withalJazeera journalist Ahmad Zaidan, asserting that the United States could be tracking his movements through devices implanted in his equipment, or by satellite.

"You must keep in mind the possibility, however, slight, that journalists can be under surveillance that neither we nor they can perceive, either on the ground or via satellite," he wrote.


Even asalQaedacame under growing pressure,binLadenand his aides planned a media campaign to mark the 10th anniversary of the September 11, 2001 attacks onNewYork and Washington, thedocumentsshow. They plotted diplomatic strategy and opined on climate change and the U.S. financialcollapse.

In a undated letter "To the American people," thealQaedachief chides Obama for failing to end the war in Afghanistan; and accurately predicts that the U.S. president's plan for ending the Israeli-Palestinian conflict will fail.

On April 28, 2011, just four days before his death,binLadenwas editing a document he had written on the Arab Spring revolutions.

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AlQaeda's leadersalso urged further attacks on the United States. "We need to extend and develop our operations in America and not keep it limited to blowing up airplanes," says a letter, apparently written bybinLaden, to Nasiral-Wuhayshi, head ofalQaeda's Yemen branch.

BinLaden"was still sort of thinking in very kind of grand schemes, and still ... trying to reclaim that 9/11 'victory'," said one of the senior intelligence officials, speaking on condition of anonymity.

But he was "somewhat out of touch with the (actual) capabilities of his organization," the officialsaid.

Thedocumentsshowthe strains of managingalQaeda's externalnetworks, including identifying capable leaders and finding resources to fund operations abroad.

One associate, who signed his 2009 note simply as "Your beloved "Atiyah," acknowledged troubles replacing an ineffective leader for externaloperations, saying some of the best candidates were dead.

"There arenewbrothers, perhaps some would be suitable in the future, but not now," he wrote.

Suspicion of tracking devices pops up again and again in the group's writings. The concern may have been merited - the United States conducts extensive electronic surveillance onalQaedaand other Islamic militant groups.

Abu Abdallahal-Halabi - who the U.S. Treasury has identified as a name used bybinLaden's son-in law Muhammad Abdallah Hasan Abu-Al-Khayr - writes in a letter to "my esteemed brother Khalid" about intercepting messages of "spies" in Pakistan, who he said would facilitate air strikes onalQaedaoperatives by marking cars with infrared streaks that can be seen with night vision equipment.

In another,binLaden, writing under the pseudonym Abu Abdallah, expressesalarm over his wife's visit to a dentist while in Iran, worrying that a tracking chip could have been implanted with her dentalfilling.

"The size of the chip is about the length of a grain of wheat and the width of a fine piece of vermicelli," he wrote.

The letter ended with this instruction: "Please destroy this letter after reading it."