In an audio message posted on Web sites commonly used by Islamic militants, Ayman al-Zawahiri, Al Qaeda's second in command, called on Muslims to attack Israeli and Western targets around the world in response to Israel's military action against Hamas in Gaza.

The message, which was posted on January 6, 2009, and titled "The Massacre of Gaza and the Siege of the Traitors," urges Muslims to "perform the duty of individual jihad" and to "fight against the Zionist-Christian campaign."

"Strike its interests wherever you encounter them...thwart the efforts of these traitors by striking the interests of the enemies of Islam - namely, the Christians and the Jews - wherever and by whatever means you can," Zawahiri said.

Zawahiri also expressed Al Qaeda's solidarity with Palestinians, saying "My Muslim brothers and mujahedeen in Gaza and all over Palestine, with the help of Allah we are with you in the battle, we will direct our strikes against the crusader Jewish coalition wherever we can."

In addition, Zawahiri pledged that America "will certainly not even dream of security before we actually live in security in Palestine."

In the audio message, produced by Al Qaeda's media wing Al Sahab, Zawahiri blames President-elect Barack Obama for the operation in Gaza, saying that "he is killing your brothers and sisters in Gaza without any mercy or compassion."  Zawahiri also accuses Egyptian president Hosni Mubarak as being a "criminal traitor" for keeping Egypt's border with Gaza closed since Hamas came to power.

The recording, which has not been immediately verified for authenticity, was accompanied by a still photograph of Zawahiri with a gun on his lap and a picture of an apparently injured Palestinian child receiving treatment.