We have launched an investigation into who secretly filmed the execution, obviously filmed with a mobile phone, and distributed it, the official told Xinhua on condition of anonymity. The two-and-a-half minute film was first broadcast by the pan-Arab al-Jazeera TV channel on Sunday and widely circulated on the Internet.

In the film, Saddam was seen taunted by Shiite witnesses at the very last moments of his life, including one who shouted the name of a radical Shiite cleric --"Muqtada, Muqtada, Muqtada. "Saddam was also seen sneeringly smiled at those taunting him from below the gallows and responded, "is that the manhood you have." Then he began reciting the Shahada, a Muslim prayer in the footage.

Saddam's hanging sparked anger in Iraq's Sunni provinces and many mourners arrived in Tikrit and Awja town from Anbar, Diyalaand Mosul. Thousands had poured into Saddam's hometown of Tikrit since Tuesday morning.

Analysts said the Sunni Arab used the footage to prove that Shiite militia, namely Mehdi Army, have infiltrated the security forces.

On the other hand, the Shiite would say the footage did not show much ill treatment for Saddam as he did worse for them during his era, analysts said.