ASHINGTON, Nov. 18 — United States intelligence officials have concluded that a recently recorded audiotape that was broadcast on an Arab television network last week is genuine and contains the voice of Osama bin Laden, apparently ending months of debate in the government over whether the elusive terrorist leader is still alive.

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An American intelligence official said today that an "extensive analysis" of the audiotape conducted over several days had convinced intelligence experts that the tape "almost certainly" contained the voice of Mr. bin Laden.

No evidence that the tape is a hoax could be detected, but intelligence officials say 100 percent certainty is impossible given the poor quality of the recording.

The tape, on which the voice said to be Mr. bin Laden's makes several references to recent terrorist attacks, was recorded sometime within the last several weeks. It has been examined by experts from the Central Intelligence Agency and the National Security Agency.

"The intelligence experts do believe that the tape is genuine," said Scott McClellan, a White House spokesman.

The assessment today that it really is Mr. bin Laden's voice on the tape came after several days in which officials had offered more guarded assessments of the tape's authenticity.

Officials said the more definitive judgment was the result of an accumulation of evidence that was all pointing in the same direction, ranging from the opinions of linguists and translators at the C.I.A. and N.S.A. and Qaeda detainees familiar with Mr. bin Laden's voice, as well as a digital analysis of the tape that indicated it had not been altered.

"At this point, there is no evidence to indicate and no reason to believe that the tape was manufactured or altered," an intelligence official said.

The technical analysis included the use of voiceprint matching, which consists of electronically comparing past samples of Mr. bin Laden's voice with the voice on the audiotape. Officials said that the voiceprint was not a 100 percent match, but that it came close.

One obstacle to making an even more definitive voiceprint match was the poor quality of the recording on the tape. American experts believe that Mr. bin Laden's message was recorded or rerecorded over a telephone line at some point. United States intelligence officials said outside technical experts had been brought in to help in the process of determining the tape's authenticity.

The more definitive statement about the tape clearly shows that the United States intelligence agencies, once divided over whether the Saudi exile had survived last year's war in Afghanistan, has now reached a consensus that he is still at large.

"One of the messages that I think bin Laden is trying to get out, both to his supporters and to the world, is `I'm alive,' " said Senator Richard C. Shelby, the Alabama Republican who is vice chairman of the Intelligence Committee.

The tape offers the first hard evidence of that since last December, when Mr. bin Laden was overheard in intercepted radio transmissions giving orders to Qaeda fighters in the Tora Bora region of Afghanistan. As time passed without any hard evidence that he had survived the American bombing campaign in Afghanistan, some counterterrorism experts in the government came to believe that he was dead, and President Bush said publicly several times in recent months that he did not know whether Mr. bin Laden was dead or alive.

The Saudi exile's re-emergence has prompted a new round of questions about the amount of progress the United States has made in the global campaign against terrorism, and whether the administration has been distracted from fighting Al Qaeda by its focus on a possible war with Iraq. Late last week, leading Democrats in Congress, including the Senate majority leader, Tom Daschle, said the failure to find Mr. bin Laden had called into question the antiterror effort. "We can't find bin Laden, we haven't made real progress in finding key elements of Al Qaeda," Mr. Daschle said.

The administration has dismissed the criticism, and officials say a series of recent operations in which senior Qaeda operatives have been captured or killed underscored the progress they have made in disrupting the terror network's operations.

But administration officials acknowledge that the bin Laden tape may be a sign that Al Qaeda is planning another wave of attacks against American and other Western targets.