WASHINGTON — Newly released documents recovered from the compound where Osama bin Laden was killed show that al-Qaeda’s leaders were frustrated in their efforts to manage an emerging group of distant affiliates that showed little discipline or willingness to take direction.

The letters include chilling admonitions to remain focused on killing Americans, cast doubt on suspicions that the governments of Pakistan and Iran collaborated with the terrorist group, and reveal bin Laden’s suspicions about a U.S.-born cleric who was rising through the ranks of al-Qaeda’s group in Yemen.

The documents declassified by the Obama administration represent only a small fraction of the trove of material recovered in the bin Laden raid, a sample that could sow discord within the terrorist network.

The files also provide an intriguing, up-close glimpse into the aging al-Qaeda founder’s thoughts as his life neared its end.

“Our strength is limited,” bin Laden wrote in a 2010 letter that compares the United States to a tree with branches that project across the world.

“So our best way to cut the tree is to concentrate on sawing the trunk.”

The details are embedded in a collection of 17 files that were made available online by the Combating Terrorism Center at the U.S. Military Academy at West Point, an organization that had exclusive access to the materials for several months and issued a report summarizing its findings.

The release, which came one year and one day after bin Laden was killed by U.S. Navy SEALs, represents a sample selected by the Obama administration at a time when the president is seeking to make its counterterrorism achievements a central part of his re-election campaign.

Obama and senior administration officials have used the anniversary of the raid to call attention to the president’s role in approving the operation, and question whether his rival, Republican candidate Mitt Romney, would have done the same.

At a time when U.S. intelligence officials regard al-Qaeda’s regional affiliates as a more pressing threat than the core group based in Pakistan, the documents show deep divisions among al-Qaeda leaders over how to handle the disparate groups.

In the 2010 letter to one of his top deputies, bin Laden expressed alarm over the “increased mistakes” committed by the “brothers” in countries including Iraq and Yemen, and he pushed to bring the groups in line.

Bin Laden and others were frustrated with the groups’ attacks on Muslims, clumsy media operations and reluctance to focus their energies on attacking the United States and its Western allies.

Bin Laden appeared to harbor doubts about Anwar al-Awlaki, the American-born propagandist for al-Qaeda’s affiliate in Yemen.

When the leader of al-Qaeda in the Arabian Peninsula, or AQAP as the affiliate is known, proposed that Awlaki take over the leadership role, bin Laden said no.

Awlaki should “remain in his position,” bin Laden said, and instructed AQAP chief Nasir al-Wuhayshi to provide a fuller resume for Awlaki, and wait until he had been tested in battle.