Al-Qaeda's second-in-command, in an internet message, called on Muslims on Tuesday to strike Western and Israeli targets around the world over Israel's raids on the Gaza Strip, and accused US President-elect Barack Obama of complicity.
"Hit the interests of the Zionists and crusaders wherever and in whichever way you can," Ayman al-Zawahiri said in an audio tape posted on Islamist websites.
"What you are facing now ... is a link in a chain in the Zionist crusader campaign on Muslims and Islam," Zawahiri said. "These attacks are Obama's present to you (Palestinians) before he takes office."
Zawahiri said the Gaza attacks had exposed Obama of whom he said: "The US lying (propaganda) machine had tried to portray to the world as a savior who would change US policy."
Obama, breaking his silence about the fighting between Israeli troops and Palestinian militants, expressed deep concern on Tuesday about civilian deaths in Gaza and in Israel and vowed to push for Middle East peace when he takes power.
Zawahiri, an Egyptian, blasted Egypt's President Hosni Mubarak as a "traitor" for failing to back Palestinians in the face of Israel's blockade of the Gaza Strip.
He called for mass strikes in Egypt and said an Egyptian soldier who shot dead several Israeli tourists in Egypt in 1985 was "an example to follow for the zealous and free in the Egyptian army".
The audio tape, produced by al-Qaeda's media arm As-Sahab, was part a video carrying a still photograph of Zawahiri and that of a Palestinian child receiving emergency treatment after apparently being wounded in the Israeli attacks, which have killed at least 631 Palestinians in the past 11 days.