TIMELINE: Messages attributed to al Qaeda's Zawahri

(Reuters) - At least 50 messages have been broadcast by al Qaeda's Osama bin Laden, Ayman al-Zawahri and their allies since the September 11 attacks on the United States in 2001.

Following is a timeline of major statements attributed to Zawahri in the past year.

April 2, 2008 - In an audio message, Zawahri denounces the United Nations, vows to attack Jews both within and outside Israel and says bin Laden is alive and well.

April 18 - Zawahri mocks Bush's decision to suspend troop withdrawals from Iraq, saying the U.S. president was scared of admitting defeat. Zawahri also mocks hopes that the Awakening Councils, security units created by Sunni Arab tribal groups to fight al Qaeda in Iraq, will restore stability to the country.

April 22 - Zawahri says in the second and final installment of his answers to questions compiled by Islamist websites that The Islamic State in Iraq remains the main force confronting the "crusaders" and their collaborators.

-- Zawahri also says U.S.-led forces are losing the battle against the Taliban in Afghanistan.

June 4 - In an Internet recording, Zawahri urges Palestinians to step up suicide and rocket attacks against Israel.

August 11 - An audio tape purportedly made by Zawahri accused President Pervez Musharraf and other politicians of trying to destabilize Pakistan at the behest of the United States.

August 22 - Zawahri in a videotape on the Internet eulogizes militants killed in a suspected U.S. air strike in Pakistan's border region in July.

September 8 - Al Qaeda issues a video in which Zawahri accuses Iran of taking part in a Western "Crusader" war against Islam.

November 19 - Zawahri warns U.S. president-elect Obama in a new taped message that he will fail if he follows the policies of President George W. Bush. He also criticizes Obama for vowing to back Israel during his campaign.

December 1 - Qaeda's second in command praises as "steadfast heroes" three militants executed for the 2002 Bali bombings, vowing that the executions would prompt Islamists to step up their anti-Western fight.

January 6, 2009 - Zawahri calls on Muslims to strike Western and Israeli targets around the world over Israel's Gaza raids, and accuses U.S. President-elect Barack Obama of complicity. Zawahri, an Egyptian, blasted Egypt's President Hosni Mubarak as a "traitor" for failing to back Palestinians.

February 3 - Zawahri dismisses Obama's expression of concern over killings in Gaza as an empty gesture and says Washington remains a main enemy of Muslims.

Feb 23 - In a recording posted on the Internet, Zawahri urges Palestinians in the Hamas-controlled Gaza Strip not to succumb to Arab pressure for a truce with Israel and vows to support fighting against the Jewish state.

March 24 - Zawahri in an Internet message urges Sudan to prepare for guerrilla war against the West after President Omar Hassan al-Bashir's war crimes indictment by the International Criminal Court (ICC).

June 2 - Zawahri urges Egyptians to reject a visit by Obama to Egypt during which he plans to deliver a message to Muslims. He described Obama as a "criminal" and said his "messages to Muslims had already been received (through) ... a bloody campaign against Muslims in Swat" in Pakistan.

Sept 22 - Zawahri and other al Qaeda leaders appear in a 106-minute Arabic language video marking the September 11, 2001 attacks. They speak of events over the past year including the global financial crisis and the Obama's election.