The security transfer in Iraq's Anbar province originally was set for June, but it has been delayed twice.

The first postponement was blamed on a sandstorm, but days before the ceremony was to take place, there was also a suicide bombing at a meeting of tribal sheikhs in an Anbar town west of Baghdad.

The official said the handover was rescheduled after the sandstorm, but a new transfer date was not announced. The transfer then was delayed because Iraqi officials disagreed over how they would handle certain issues, the official said.

More than 25,000 US troops, mostly Marines, serve in Anbar province. They will remain for the time being, the official said, but will shift their mission to supporting Iraqi forces when needed.

The turnover comes as Gen. David Petraeus - the top US commander in Iraq -- is scheduled to begin making his recommendations to President Bush and Defense Secretary Robert Gates on US troop withdrawals from Iraq, the official said.

The proposals could come as soon as in late August or early September and could cover withdrawals over the next six to eight months, the official said.