Al Qaeda's second-in-command urged Muslims to keep up attacks on the "criminal" United States and criticised US president-elect Barack Obama for promising to back Israel.
Ayman al-Zawahri also warned Mr Obama of failure should he pursue the policies of President George W. Bush, according to a tape published Wednesday by the SITE Intelligence Group, a US organisation that monitors Islamist militant groups.
The Egyptian militant also criticised Mr Obama, born to a Muslim Kenyan father, for what he described as turning his back on his Muslim roots.
"The Muslim nation received with extreme bitterness your hypocritical...stance towards Israel," he said. "You were born to a Muslim father, but you chose to stand with the enemies of Muslims."
An Obama spokeswoman in Washington said the president-elect's office was not planning to comment.
A US counterterrorism official said Zawahri's message showed that the militant network - which masterminded the September 11th, 2001, attacks on the United States - was isolated but still a threat.
"The message...is remarkable chiefly as an additional sign that al-Qaeda is out of touch with so much of the world," the official said.
During a visit to Israel in July, Mr Obama assured Israel and its US Jewish supporters he was a friend who would not press for peace concessions that would compromise its security.
Reuters