WASHINGTON -- Counterterrorism officials pored over the audio recording believed to be from Osama bin Laden on Wednesday, seeking clues about the terror head's whereabouts and possible intentions to strike the U.S. and its allies.

Officials said they were treating the tape as a real message from al-Qaida's missing leader, even as the CIA and National Security Agency conducted a technical analysis of the tape aimed at authenticating it.

President Bush said he was taking the message "very seriously."

"Whoever put the tape out has put the world on notice yet again that we're at war," the president said after a Cabinet meeting at the White House.

The president bristled when asked if bin Laden should have been captured sooner by U.S. and coalition forces. "We're making great progress in the war on terror. Slowly, but surely, we are dismantling the terrorist network," he said.

Not 100 percent sure

Many intelligence analysts have concluded the audiotape almost certainly was made by bin Laden, said a senior law enforcement official, speaking on condition of anonymity. Other U.S. officials were more conservative, saying it probably came from bin Laden.

"They can't get to 100 percent certainty, but they're sure," the law enforcement official said. "He's alive. We have to work on that assumption, and we are."

The official, who participated in a high-level briefing by CIA and NSA officials, said analysts are now trying to determine whether bin Laden placed cryptic messages in the recording to order followers into action.

The tape, if validated, would be the first confirmation in a year that bin Laden is alive.

The speaker on the tape sounds undeterred by the loss of bin Laden's home in the Taliban's Afghanistan or by the death and capture of several of his closest lieutenants.

"Why should fear, killing, destruction, displacement, orphaning and widowing continue to be our lot, while security, stability and happiness be your lot? This is unfair. It is time we get even," he says, sounding as if he is reading.

Aired Tuesday

The message, aired Tuesday on the al-Jazeera Arabic television network, appears aimed at both Westerners and al-Qaida loyalists, officials said.

"Assuming it is in fact authentic, it is an effort to boost morale among the rank and file," said one official familiar with the tape, speaking on condition of anonymity. "It is an effort to show members of al-Qaida that the top leadership is still around. It could also signal future attacks."

The recording appears to have been made sometime in the past two weeks. The speaker appears to refer to the Oct. 28 shooting death of a U.S. diplomat in Amman, Jordan. U.S. officials don't know if al-Qaida conducted that attack. The speaker also praises the bombing in Bali, Indonesia, last month, that left close to 200 people dead.

He also takes on issues that resonate in the Islamic world -- the U.S. threat of war in Iraq and the ongoing violence between Israelis and Palestinians. He threatens six U.S. allies: Britain, France, Italy, Germany, Canada and Australia.

U.S. officials also noted that the tape mentions three top Bush administration officials by name: Vice President Dick Cheney, Defense Secretary Donald Rumsfeld, and Secretary of State Colin Powell.

"It personalizes things to a degree we hadn't seen before," one official said.