The American-born al-Awlaki said U.S. cockiness will lead to the country's ruin, ABC News reported.
"Imperial hubris is leading (America) to its fate: a war of attrition, a continuous hemorrhage that would end with the fall and splintering of the United States of America," al-Awlaki said.
He said U.S. Army Maj. Nidal Hassan, the accused Fort Hood shooter, and Umar Farouk Abdulmutallab, the Nigerian charged in the failed Christmas Day bombing of an American jetliner, were inspired by U.S. foreign policy.
"America refuses to admit that its foreign policies are the reason behind a man like Nidal Hassan, born and raised in the U.S., turning his guns against American soldiers," said al-Awlaki, who also met with Abdulmutallab before his attempted attack.
A U.S. counterterrorism official said the tape is probably authentic but has little import, ABC said.
"It's not just extremist bravado, it's trash," the official, whose name was not reported, said.
Al-Awlaki also gave an explanation for his decision to fight the country where he was raised.
"I could not reconcile between living in the U.S. and being a Muslim, and I eventually came to the conclusion that jihad against America is binding upon myself, just as it is binding on every other able Muslim," he said.