But the voice on the tape, aired on al-Jazeera a week after a US strike against al-Qaeda militants in Pakistan, also offered the American people a conditional "long term truce".
Washington has flatly rejected the offer, as CIA analysts concluded that the voice on the audiotape was indeed that of bin Laden.
"Following a technical analysis... the CIA assesses that it is voice of Osama bin Laden," said the official, who asked not to be identified.
Rare message
The tape marks the first time that bin Laden has been heard from in more than a year, with his silence adding to feverish speculation about the fate of the man behind the September 11, 2001 attacks on the United States and a host of other terrorist strikes.
"The delay in similar attacks is not because of the failure to penetrate security measures taken ... These operations are being prepared and you will see them in your heartland when they are ready," the voice said, addressing the American people.
"Read history ... We are a people that seeks revenge ... until we avenge as (we did) on September 11, God willing," he said.
"We have no objection to offering you a long-term truce based on fair conditions that we will adhere to, because we are a nation that has been forbidden by God to backstab or lie," he said.
"The truce would offer the two parties peace and stability to build Iraq and Afghanistan which were destroyed by the war. There is nothing shameful in (finding) a solution," he said.
White House spokesman Scott McClellan rejected the offer.
"We do not negotiate with terrorists. We put them out of business," he said.
"If there is any actionable intelligence (on the tape), we will act on it," he told reporters before the CIA announced it had verified the voice was bin Laden's.
US cautious
The US administration has traditionally been cautious about reacting to such tapes before the veracity is confirmed.
The Saudi-born militant had not been heard of since a December 27, 2004 audiotape in which he anointed Abu Musab al-Zarqawi, Iraq's most wanted man, as al-Qaeda's leader in the war-torn country.
Bin Laden's last video appearance was on December 16, 2004 when he also called on his fighters to strike Gulf oil supplies and warned Saudi leaders they risked a popular uprising.
On Thursday, Qatar-based al-Jazeera broadcast three extracts from the poor-quality audiotape lasting just a few minutes.
The newsreader said the tape dated back to the Muslim calendar month of Zi Al Qadah, which corresponds to December 2005, but gave no further details.