Baghdad/Tehran, Aug 26 (DPA) Abdulaziz al-Hakim, the leader of one of Iraq's most powerful Shia political groups, died at a Tehran hospital Wednesday after a battle with cancer, Iranian media reported.

The head of the Supreme Iraqi Islamic Council died shortly after the party's television station al-Furat announced that al-Hakim was in critical condition in Iran where he has been receiving treatment from lung cancer for the past four months.

'We offer our condolences to the Iraqi people and the Islamic nation for the death of Abdulaziz al-Hakim who was an elder brother and a strong pillar during our fight against the former regime and during the reconstruction of the new Iraq,' Prime Minister Nuri al-Maliki said in a statement.

Al-Hakim has been the head of the council since the assassination of his elder brother Mohamed Baqer al-Hakim in an explosion in the southern Iraqi holy city of Najaf in 2003.

His family suffered particularly in Iraq's long political struggle, and lost six brothers to assassinations ordered by Saddam Hussein. Having been imprisoned three times for insurgency activities under Saddam, al-Hakim went into exile in Iran in 1980.

The Supreme Iraqi Islamic Council, which was founded in the early 1980s with the help of Iran, is a powerful party that has long formed the backbone of the dominant Shia United Iraqi Alliance (UIA), Iraq's ruling Shia coalition of over 20 groups.

The council, the largest party in the national parliament, maintains good relations with Washington. Al-Hakim was a member of the US-appointed Iraqi Governing Council after the US-led invasion in 2003. Due to his clerical status, he does not hold a post in the Iraqi government.