Forty to 50 posts will be open next year in the embassy, located in Baghdad's fortified green zone.

Until now postings have been staffed on a voluntary basis and have often been hard to fill.

Up to 300 US diplomats will be notified that they are "prime candidates" for one-year terms in Iraq.

Only those with compelling reasons, such as medical problems or extreme personal hardships, will be exempt from disciplinary action if they refuse.