(adds quote) BAGHDAD, Feb 24 (Reuters) - U.S. and Iraqi security forces have killed around 400 suspected militants since the start of a major crackdown to stem violence in Baghdad, Prime Minister Nuri al-Maliki said on Saturday. Maliki visited the command centre for the operation which was launched 10 days ago and urged security forces taking part in it not to be influenced by sectarian loyalties. He told reporters 426 suspected militants had been detained in the crackdown "and around that number have been killed". Maliki, a Shi'ite Islamist criticised for not doing enough to combat Shi'ite militias, has vowed to deal even-handedly with both Shi'ite and Sunni Muslims responsible for violence that had been killing hundreds every week. A statement from his office said the prime minister reminded security forces to "respect the citizen" during searches. "We will punish all those who ease up on searches involving people from their sect or ethnicity," the statement said. Washington calls the Mehdi Army, a militia loyal to radical Shi'ite cleric Moqtada al-Sadr, the greatest threat to security in Iraq. Sunni Arabs blame it for running death squads, a charge Sadr denies. Maliki said the crackdown would be extended to other provinces once Baghdad was stabilised. "I'm very optimistic about this plan because of the cooperation between the people and the security forces," he said.
