The move could leave his party, the Sadrist Movement, with little political influence as Iraq prepares for provincial and national elections. As an independent, however, it would leave Sadr with an active voice in the Iraqi political system without lending credibility to a U.S.-backed system of government, the Iraqi satellite channel al-Sumaria reported.

Sadr spokesman Saleh al-Obeidi said the Sadrist Movement was waiting for U.S. forces to end their occupation of Iraq before preparing for a significant role in Baghdad.

Luwaa Sumaisem, the chief of the Sadrist Movement in the Iraqi Parliament, added the party would maintain its presence in government to help rebuild the country.

Sadr formally disbanded his militia, the Mehdi Army, earlier this year, calling for its members to focus their energy instead on social services. Some Mehdi Army fighters remain active, however.

The revered cleric is believed to be in Iran furthering his clerical studies.