One of Iraq's most powerful figures, who has been at the centre of a long crisis over forming a government, has announced his retirement from political life. Moqtada al-Sadr, a firebrand Shia cleric with millions of followers, announced his decision on the social media platform, Twitter.<br />''<br />''In his statement, Mr. Sadr announced his final retirement and the closure of all his institutions across the country. Some religious sites linked to his movement will remain open.<br />''<br />''Hundreds of supporters of 48-year-old Moqtada al-Sadr have been camped outside the Iraqi Parliament for weeks after twice storming it in protest at the political deadlock. His forces were prominent in fighting US troops after the 2003 invasion.<br />''<br />''<br />''<span style="color: #222222;">Mr. Sadr's announcement comes two days after he called for all parties and figures involved in political life following the US-led invasion of Iraq to quit. </span><br />