CAIRO, Egypt (AP) -- Osama bin Laden's deputy urged Muslims on Monday to attack Jewish and American targets worldwide in retaliation for Israeli attacks in the Gaza Strip, intensifying an al-Qaida push to use Arab anger to rally support for the terror network.
The tape by Ayman al-Zawahri came just days after two messages from bin Laden, who called for a holy war on behalf of the Palestinians and warned of a "severe" reaction against Europe over the republishing of newspaper cartoons seen as insulting Islam's Prophet Muhammad.
The string of messages has raised fears that al-Qaida is planning new attacks in the West - or that it hopes to inspire sympathizers to carry out violence. The broader goal may be to show supporters that al-Qaida can open a new front against Israel.
Bin Laden and al-Zawahri have frequently referred to the Palestinian cause in past messages, usually in broader terms of liberating Jerusalem and denouncing Israeli violence.
Al-Qaida is not known to have a direct presence in Israel or the Palestinian territories, and its sympathizers often post messages on Islamic militant Web forums asking why the terror network has not attacked Israel on its soil or gotten more involved on the Palestinian front.
Bruce Hoffman, a counterterrorism expert, said that with al-Qaida in Iraq suffering setbacks, al-Qaida "has to look further afield and at least give an impression of an upward trajectory, that it's operating across the Middle East."
He noted al-Qaida's media arm, Al-Sahab, has dramatically stepped up output of audio and video tapes, issuing an average of one every three days in 2007, or more than double the 2006 rate.
"There comes a time when you have to back up your words," said Hoffman, a professor at Georgetown University. "With the increased drumbeat of propaganda ... it becomes an element of necessity - if you're talking so much you have to do something."
"Perhaps they don't have the ability to attack the United States, so they may turn to the next best enemy, either Israel or Europe," he added.
Al-Zawahri's call for attacks had a more immediate and urgent tone than past messages.
"Muslims, today is your day. Strike the interests of the Jews, the Americans, and all those who participated in the attack on Muslims," he said. "Monitor the targets, collect money, prepare the equipment, plan with precision, and then - while relying on God - assault, seeking martyrdom and paradise."
He said attacks should not be limited to Israel or Palestinian territory.
"Today there is no room for he who says that we should only fight the Jews in Palestine," he said. "Let us strike their interests everywhere, just like they gathered against us from everywhere."
The authenticity of the tape could not be independently confirmed. But the voice resembled that of al-Zawahri on previous audio and video tapes confirmed to be his. It was posted on an Islamic militant Web site where al-Qaida usually releases its statements.
Israeli officials declined to comment on the tape. Israel conducted a weeklong offensive in Gaza that ended in early March, seeking out Palestinian militants who fire rockets into Israel. The Israeli assault killed more than 120 people, including many civilians, and caused heavy damage - all aired prominently on Arab TV news channels.
The only previous attack blamed on al-Qaida specifically targeting Israelis was in Mombasa, Kenya, six years ago, when a suicide bomber killed 16 people at a hotel full of Israelis but militants failed in a simultaneous attempt to shoot down an Israeli jetliner with missiles.
Al-Zawahri also denounced Arab leaders he accused of supporting Israel - pointing to Egypt, Saudi Arabia and Jordan, suggesting they too could be targets.
The Egyptian-born al-Zawahri accused Egyptian President Hosni Mubarak of colluding with Israel in the siege of Gaza. Egypt has sealed its border with Gaza since the Palestinian militant group Hamas took over the territory last year.
He said Mubarak "repeats the same dirty role" as the Lebanese Phalangists - a Christian militia that was allied with Israel in Lebanon's 1975-90 civil war and was blamed in the massacre of Palestinians in the Beirut camps of Sabra and Shatila.
"The roles are the same, even if the faces change - the same betrayal even if the names have changed," said al-Zawahri.