Rebel cleric Muqtada Sadr’s grip on Imam Ali Mosque appeared less certain late Friday after a chaotic day in which some of his fighters were captured attempting to flee this holy city and his representatives vowed to remove weapons from the shrine. Earlier in the day, Iraqi government officials had reported — erroneously — that Sadr’s forces had been routed from the mosque. But Friday evening, the militia still maintained control of the shrine, although a Sadr spokesman said negotiations were underway to turn it over to Grand Ayatollah Ali Sistani, Iraq’s top Shiite cleric. Aides to Sistani, who is in London recovering from a heart procedure, said they would accept Sadr’s offer on condition that all of his men left the mosque, its doors were locked and its contents inventoried. About OODA Analyst