WASHINGTON — American intelligence analysts have concluded Al Qaeda has rebuilt its operating capability to a level not seen since just before the September 11, 2001, attacks, the Associated Press has learned.

The conclusion suggests that the group has been able to rebuild despite nearly six years of bombings, war, and other tactics aimed at crippling it.

Still, numerous government officials say they know of no specific, credible threat of a new attack. A counterterrorism official familiar with a five-page summary of the new government threat assessment called it a stark appraisal that will be discussed at the White House today as part of a broader meeting on an upcoming National Intelligence Estimate. The official and others spoke on condition of anonymity because the secret report remains classified.

Counterterrorism analysts produced the document, titled “Al Qaeda better positioned to strike the West.” The document pays special heed to the terror group’s safe haven in Pakistan and makes a range of observations about the threat posed to the United States and its allies, officials said.

Al Qaeda is “considerably operationally stronger than a year ago” and has “regrouped to an extent not seen since 2001,” the official said, paraphrasing the report’s conclusions. “They are showing greater and greater ability to plan attacks in Europe and the United States.”

The group also has created “the most robust training program since 2001, with an interest in using European operatives,” the official quoted the report as saying. At the same time, this official said, the report speaks of “significant gaps in intelligence” so American authorities may be ignorant of potential or planned attacks.

John Kringen, who heads the CIA’s analysis directorate, echoed the concerns about Al Qaeda’s resurgence during testimony and conversations with reporters at a House Armed Services Committee hearing on yesterday.

“They seem to be fairly well settled into the safe haven and the ungoverned spaces of Pakistan,” Mr. Kringen testified. “We see more training. We see more money. We see more communications. We see that activity rising.”

The threat assessment comes as the National Intelligence Council is preparing a National Intelligence Estimate focusing on threats to America. A senior intelligence official said the document has been in the works for roughly two years.