NAJAF, Iraq (Reuters) - Abdul Aziz al-Hakim, one of Iraq's most powerful Shi'ite Muslim leaders, was buried in the holy city of Najaf on Saturday, three days after his death cast more uncertainty over Iraq's turbulent politics.
Hakim, 59, a popular cleric who headed the powerful Shi'ite Supreme Islamic Iraqi Council (ISCI), died on Wednesday in Tehran, where he was being treated for lung cancer.
He was buried beside his elder brother Muhammad Baqer al-Hakim, who was killed in a 2003 bombing that was claimed by al Qaeda. Hakim took charge of ISCI from his brother.
Thousands of Hakim's supporters in black or white robes thronged streets beside a motorcade carrying his coffin to the burial site. They waved green flags and held banners. One read: "Goodbye, Abu Ammar", an affectionate name for the cleric.
Some prayed, others beat their heads and chests with their hands in a traditional mourning ritual. One of his aides placed his trademark black turban on the car's roof.
Supporters carried his coffin, wrapped in a green shroud to the Imam Ali shrine, one of Shi'ite Islam's holiest sites. He was interred in a cemetery about a mile (1.5 km) away.
"Iraq has lost someone who can never be replaced," said 39-year-old government employee Ali Mohammed Abbas. "He was a national and religious figure and a guide for all Iraqi people."
ISCI on Monday said it would lead a new, mostly Shi'ite alliance to compete in January's national polls without Prime Minister Nuri al-Maliki's small Dawa party, raising questions about possible disunity amongst Iraq's Shi'ite majority.
Hakim's son, Ammar al-Hakim, who has been groomed to take over ISCI but may yet face internal leadership challenges, has urged those outside the new alliance to join it.
ISCI was founded in Iran in exile during Iraqi Sunni leader Saddam Hussein's rule. It has close ties to Iran's rulers.
Iran's Foreign Minister Manouchehr Mottaki said in Iraq: "(Hakim's) death is a loss for the political process. His eminence made sacrifices to liberate Iraq from dictatorship."
ISCI derives much 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 other violence. Saddam killed eight of Hakim's brothers and many more of his family.
ISCI and Maliki's Dawa party swept to power in 2005 polls as part of a broad Shi'ite coalition, but over the past year wrangling over alliances has intensified.
Violence has fallen overall in Iraq, but a spike in major attacks in the past month is expected to continue ahead of the polls and as U.S. forces prepare to withdraw by the end of 2011.
(Additional reporting by Muhanad Mohammed)