Following is a timeline of some of the major recent statements attributed to Ayman al-Zawahri.
June 2, 2009 - Zawahri urges Egyptians to reject a visit by U.S. President Barack Obama to Egypt during which he delivered 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.
July 19, 2010 - In an Internet message, Zawahri mocks Obama for voicing confidence over victory in Afghanistan. He also says Arab government leaders allied to the West are more harmful to the Palestinians than Israel.
July 27 - Zawahri, in an audio recording, condemns a French move to ban Islamic face veils and, urges Yemeni clerics to call for jihad against U.S. operations in Yemen.
Sept. 15 - Zawahri releases an audio recording calling on Pakistanis to revolt.
Nov. 4 - In a recording posted on the internet, Zawahri calls for retaliation against the United States for sentencing a female Pakistani neuroscientist to life in prison for shooting at FBI agents and soldiers.
-- Aafia Siddiqui was arrested in Afghanistan in 2008 by Afghan police, who said she was carrying 900 grams (2 lb) of sodium cyanide and crumpled notes referring to mass-casualty attacks and New York landmarks.
Feb. 18, 2011 - Zawahri condemns Egypt's regime under toppled leader Hosni Mubarak as corrupt, and praises an Islamic state as an appropriate alternative, in an audio recording posted on the Internet.
April 15 - Zawahri says Muslims should fight NATO in Libya in an audio message. "I want to say to our Muslim brothers in Libya, Tunisia, Algeria, and the rest of the Muslim countries, that if the Americans and the NATO forces enter Libya, then their neighbours....should rise up and fight both the mercenaries of Gaddafi and the rest of NATO."
May 2 - Osama Bin Laden is killed in Pakistan by U.S. forces after a 10-year hunt.
June 8 - Zawahri mourns bin Laden in a 28-minute eulogy on YouTube. He calls on Pakistanis to rise against what he called their corrupt rulers "just as your brothers in Tunisia, Egypt, Libya and Syria have done".
June 16 - Osama bin Laden's long-time lieutenant, Zawahri, is now the leader of al Qaeda, Al Arabiya television reports.
July 27 - Zawahri urges Syrian protesters to direct their movement also against Washington and Israel, denouncing the United States as insincere in showing solidarity with them, according to a new Internet video issued. The video carried a date in June.
-- "You are standing with your bare chests facing tank and artillery shells and helicopters," Zawahri said of the Syrians demonstrating against Assad, whom he denounced as "America's partner in the war on Islam in the name of fighting terror".
Sept 13 - Zawahri voices support in an Internet video for popular revolts shaking the Middle East, saying Arabs no longer feared the United States.
-- "Ten years have passed since the blessed attacks on New York and Washington and Pennsylvania, that mighty event which shook and continues to shake the pillars of the global crusade".
Oct 12 - Zawahri urges Algerians in a video released to follow the example of Libyans and revolt against their leaders. He also attacks military rulers in his native Egypt for maintaining close ties with Israel. (Reporting by David Cutler, London Editorial Reference Unit; email@example.com; +44 20 7542 7968; Reuters Messaging: firstname.lastname@example.org)