U.S. envoy says Iraq report will sound warning on Iran

Crocker said he was in daily contact with Petraeus but had not yet begun to draft his report, which is due to be presented on September 15 and is seen by many as a watershed moment in the war that could trigger a change in U.S. policy.

"I have come to find here in Iraq that a month is a long span of time," he said.

He said the U.S. military buildup, which has succeeded in reducing sectarian violence, and new alliances formed with Sunni Arab sheikhs that have pacified volatile Anbar province had brought Maliki's government to a cross-roads.

"This is the best chance they have had since the beginning of 2006. It is an opportunity to really start turning things around in this country. But they are going to have to move in a decisive, considered and comprehensive way."

Iraq's leaders have been meeting this week to try to find common ground and break the political logjam that has paralyzed decision-making, lost him nearly a score of ministers, and stalled agreement on key laws that Washington sees as crucial to national reconciliation.