BAGHDAD, Aug 27 (Reuters) - Iraqi populist Shi"ite Muslim cleric Moqtada al-Sadr said on Friday that he and his supporters would take part in an October general election, reversing a decision last month to stay out. Sadr"s bloc is part of a coalition that holds the most seats in parliament now, and is likely to be one of the frontrunners in the vote, which was called early by Prime Minister Mustafa Al-Kadhimi as a response to popular protests from 2019. Sadr said in a televised address that the about-face came after a number of political leaders, whom he did not identify, had written to him with a "charter for reform" to rid Iraq of corruption and mismanagement. He urged supporters to go to the polls and vote in the early election scheduled for Oct. 10. A vote for his movement, he said, would mean an Iraq liberated from foreign meddling and rampant graft. "We will enter these elections with vigour and determination, in order to save Iraq from occupation and corruption," Sadr said. Sadr, who commands a loyal following of millions of Iraqis, is one of the most powerful political leaders in Iraq and has grown his influence over state institutions in recent years. Sadr loyalists hold official posts with control of a large portion of the country"s wealth and patronage networks. Detractors accuse Sadr and his supporters, like other Iraqi parties, of being involved in corruption within state institutions - a charge Sadrists reject. Sadr, an unpredictable and wily political operator, opposes the presence of U.S. troops, of which some 2,500 remain in Iraq, and rejects the influence of neighbouring Iran - a position at odds with many rival Shi"ite politicians and armed groups who are loyal to Tehran.