Iraqi Shia cleric Moqtada al-Sadr, leader of a powerful political movement, commander of a once-feared militia and a fierce critic of the US-led invasion, has announced his exit from politics.

"I announce my non-intervention in all political affairs and that there is no bloc that represents us from now on, nor any position inside or outside the government nor parliament," Sadr said in a written statement received by AFP on Sunday.