Izzat Ibrahim al-Douri, in an audio tape aired by Aljazeera on Monday, urged an Arab summit taking place in Sudan this week to recognise the "Iraqi resistance as the sole legitimate representative of the Iraqi people" and to "boycott the regime of agents and traitors".
"You should take the necessary decisions to support the Iraqi people and their brave national resistance and its jihad until Iraq is freed," the speaker added.
Al-Douri has been accused of having a major role in many of the bloody attacks carried out by Sunni militias.
But the speaker on the tape condemned attacks on mosques, Shia holy sites and churches in Iraq.
Violence between Shia and Sunnis, who were favoured under Saddam's rule, has been rising and many fear the bloodshed could spiral out of control into a civil war.
"O faithful mujahidin, know that the bombing of the dome of ... Imam Ali and the killing of Iraqi innocents and civilians and the burning of mosques, Shia holy sites and churches, and killing based on identification cards represents the epitome of vileness, vice and a crime," the speaker said.
"And our people and resistance will take revenge on the perpetrators sooner or later," he said.
Al-Douri was vice-president and deputy chairman of Iraq's powerful Revolutionary Command Council until the 2003 US-led invasion that ousted Saddam.