Abdul Aziz Al-Hakim, the leader of one of Iraq's most powerful Shi'ite political groups and most important religious dynasties, died on Wednesday, adding to political uncertainty in a violent run-up to an election next January.

Al-Hakim, who headed the Supreme Islamic Iraqi Council (ISCI), a major partner in the Shi'ite-led government, died while undergoing treatment for cancer in Iran, party officials said.

"It is a painful event and a great tragedy," the ISCI television station quoted Ammar Al-Hakim, his son and likely successor as party leader, as saying. ISCI officials said two funerals would be held, in Iran and in Iraq.

Al-Hakim, born in 1950, took over ISCI in 2003 when his brother, Grand Ayatollah Muhammad Baqer Al-Hakim, was killed in a car bomb.

ISCI is part of Iraq's ruling Shi'ite alliance, which also includes Prime Minister Nuri Al-Maliki's Dawa party, but ISCI announced this week it would lead a new group to compete in January's polls without Al-Maliki.

The last few weeks have also seen a spate of major bomb attacks in Iraq, undermining public confidence in the Iraqi security forces who took over the prime responsibility for protecting the nation when US troops pulled out of urban centres in June.

The bombings, including two on August 19 that devastated the foreign and finance ministries and killed 95 people, also dealt a blow to Al-Maliki's efforts ahead of the January election to claim credit for a fall in overall violence in the past year.

The overtly religious ISCI became a major political player in majority Shi'ite Iraq after the 2003 US-led invasion ousted Sunni Muslim dictator Saddam Hussein, and its role in the Iraqi government was backed by the United States.

It was founded in neighbouring Shi'ite Iran, where many of its senior leaders lived for years in exile during Saddam's rule.

Although ISCI lost ground to Al-Maliki's Dawa in provincial elections last January, the well-organised and well-funded party has major clout and will be a formidable competitor in January.

ISCI has several members in top ministerial posts, and has influence in Iraq's security forces, which include members of ISCI's armed affiliate, the Badr Organisation.

ISCI derives much of its support from the Hakim family name, revered among Shi'ites for its lineage of scholars and sacrifice in the face of assaults by Saddam and later by Sunni insurgents during the bloodshed that raged after the US invasion.

Hakim's son Ammar appears to have been groomed for succession, given his regular appearances on behalf of and next to his father, but there are other key figures in the party.

In May, Hakim entrusted top ISCI member Humam Hamoudi to repair the ruling Shi'ite alliance. One of Iraq's two vice presidents, Adel Abdul-Mehdi, is also an important ISCI member with strong support within the party.

ISCI has pushed for a separate Shi'ite region in Iraq's mainly Shi'ite south, although the plan has been on the backburner since Al-Maliki's allies trounced ISCI in the local polls with a call for a strong, unified state. - Reuters