Baghdad was under tight security with roads closed to cars and additional checkpoints set up throughout the capital.

Police announced they have closed bridges leading to the south of the country in effort to block a squad of suicide bombers reported to be heading to Karbala to disrupt the Ashura ceremonies marking the death of the Imam Hussein.

As the holiest of Shia occasions, whose commemoration was banned under ousted dictator Saddam Hussein's regime, Ashura has often been the target of Sunni extremists.

In 2004, 170 people were killed in attacks in Baghdad and Karbala and another 44 died in 2005.

A day before the climax of the commemoration itself, the streets of Karbala were thronged with tens of thousands of devout Shiites chanting and beating themselves with chains to reenact the last painful days of the seventh century imam.

In Baghdad, the mournful thump of a drum announced parades of black-clad men moving across the city's car-less bridges, bearing colorful flags and remembering the death of Hussein, a grandson of the Prophet Mohammed.

On the bridge across the Tigris leading to the city's main Shia mosque, Al-Khilani, were crowds of black clad worshippers while inside, Abdel Aziz Hakim, leader of the Supreme Council of the Islamic Revolution in Iraq (SCIRI) gave a sermon.

One of the most powerful political and religious leaders in the country, Hakim took the opportunity to denounce European papers for running cartoons insulting the Muslim prophet.