Iraq's government has announced that it will enforce curfews, ban cars and close the country's borders ahead of next Saturday's constitutional referendum.
Thousands of Iraqi and coalition troops will also be on patrol to protect Iraq's more than 15 million eligible voters, as many of them cast a "yes" or "no" vote for the charter.
In Baghdad, Sunni Arab political leaders Saturday urged their community not to boycott the vote, but to cast their ballots against the charter, which they fear will divide the country.
Saturday, the Arab League sent a delegation to Baghdad ahead of the referendum. In an interview with BBC radio, League chief Amr Moussa said the situation in Iraq is so tense he fears civil war could erupt at any moment.
Meanwhile, in Baghdad, a suicide car bomber killed seven people. And the U.S. military says it has ended Operation Iron Fist, one of four operations intended to cleanse western Iraq of insurgents ahead of the vote.