Al-Qaida's number two leader has appeared in a video praising Abu Musab al-Zarqawi, the leader of al-Qaida in Iraq killed on June seventh by a U.S. air strike.

Ayman al-Zawahiri's video aired Friday on Al Jazeera.

In it, Zawahiri appeared in front of a portrait of Zarqawi. He called Zarqawi the prince of martyrs and said that no member of al-Qaida would die without avenging him.

He also criticized several Iraqi government officials and the U.S. Ambassador to Iraq.

Zawahiri did not mention Zarqawi's successor as leader of al-Qaida in Iraq, Abu Hamza al-Muhajer. The omission may mean the tape was made before Muhajer was appointed or that Zawahiri does not endorse him.

Zawahiri, along with al-Qaida chief Osama bin Laden, is thought to be hiding somewhere along the rugged border dividing Afghanistan and Pakistan.