Al-Hakim died Wednesday in Tehran after a lengthy battle with lung cancer . He was 59 . He will be buried in his hometown of Najaf , one of the holiest cities for Shiite Muslims , al-Husseini said . U.S. Ambassador to Iraq Christopher Hill and the top U.S. commander in Iraq , Gen. Ray Odierno , described him as `` a national hero '' in a joint statement that expressed sadness over the death . `` Throughout his life , His Eminence demonstrated courage and fortitude , contributing to the building of a new Iraq , '' the statement said . `` We offer our sincere condolences to his family and colleagues . Iraqi Prime Minister Nuri al-Maliki also offered condolences , saying al-Hakim was `` like an old brother . '' Al-Maliki credited him for being a `` strong supporter during the phase of fighting the ousted regime and a key figure in the process of building the new Iraq . '' Watch how al-Hakim helped shape Iraq 's future '' `` His death at this critical stage that we are passing through is a great loss for Iraq , '' al-Maliki said . Al-Hakim ended his exile
TEHRAN , Iran -LRB- CNN -RRB- -- A funeral procession for a senior Iraqi Shiite leader wound through the streets of Tehran , the Iranian capital , on Thursday . Iraqi Shiite leader Abdul Aziz al-Hakim , seen in a 2007 photo , was an ally of both the U.S. and Iran . Mourners turned out to say goodbye to Abdul Aziz al-Hakim , who spent 20 years in exile in Iran before returning to Iraq after U.S.-led forces toppled Iraqi President Saddam Hussein . The funeral procession started at the Iraqi Embassy in Tehran , said Haitham al-Husseini , a senior official with al-Hakim 's office and one of his advisers . Iraqi and Iranian government officials attended the procession with senior religious figures and some members of the Iraqi parliament . Another funeral procession is scheduled to be held Friday in Baghdad , Iraq , before the casket travels to several parts of southern Iraq with large Shiite populations . Authorities are concerned about security since Sunni insurgents have targeted large Shiite gatherings in the past . The Iraqi government announced the start of three days of mourning on Thursday , according to state television in Iraq .