WASHINGTON - In the largest call-up of U.S. diplomats since the Vietnam War, the State Department is planning to order some of its personnel to serve at the American Embassy in Iraq because of a lack of volunteers. Those designated "prime candidates" — from 200 to 300 diplomats — will be notified Monday that they have been selected for one-year postings to fill the 40 to 50 vacancies expected next year. They will have 10 days to accept or reject the position. If not enough say yes, some will be ordered to go to Iraq and face dismissal if they refuse, Harry Thomas, director general of the Foreign Service, said Friday. "Starting Nov. 12, our assignments panel will assign people to Iraq," Thomas told reporters in a conference call. "Under our system, we have all taken an oath to serve our country, we have all signed (up for) worldwide availability. "If someone decides ... they do not want to go, we will then consider appropriate action," he said. "We have many options, including dismissal from the Foreign Service." Only those with compelling reasons, such as a medical condition or extreme personal hardship, will be exempt from disciplinary action, Thomas said. He said the process of deciding who will go to Iraq should be complete by Thanksgiving. Diplomats who are forced into service in Iraq will receive the same extra hardship pay, vacation time and choice of future assignments as those who have volunteered since Secretary of State Condoleezza Rice this past summer ordered Baghdad positions to be filled before all others around the world. About 200 Foreign Service officers work in Iraq. It is certain to be unpopular due to serious security concerns in Iraq and uncertainty over the status of the private contractors who protect U.S. diplomats there, particularly after a deadly Sept. 16 shooting in which guards from Blackwater USA protecting an embassy convoy were accused of killing 17 Iraqi civilians. The union that represents U.S. diplomats, the American Foreign Service Association, has expressed deep concerns in the past about a possible move what are known as "directed assignments." But officials with the union could not be reached for comment late Friday. The move to directed assignments is rare but not unprecedented. In 1969, an entire class of entry-level diplomats was sent to Vietnam, and on a smaller scale, diplomats were required to work at various embassies in West Africa in the 1970s and 1980s. More than 1,200 of the department's 11,500 Foreign Service officers have served in Iraq since 2003, but the generous incentives have not persuaded enough diplomats to volunteer for duty in Baghdad or with the State Department's provincial reconstruction teams. When she ordered that Baghdad be given staffing priority, Rice had warned that unless more volunteers could be found, the department would have to implement directed assignments. "It is my fervent hope that we will continue to see sufficient numbers ... volunteering for Iraq service, but we must be prepared to meet our requirements in any eventuality," she said in an unclassified cable sent to all diplomatic missions abroad on June 19. That directive followed an earlier offer for any diplomats wanting to learn Arabic to leave their current post immediately for two years of language training before being posted to Iraq and an appeal from the U.S. ambassador in Baghdad, Ryan Crocker, for the urgency of the Iraq operation to be made clear to all diplomats. Crocker has repeatedly appealed to the State Department headquarters for more and better trained personnel to staff the embassy. The embassy operation had been due to move into a vast new compound last month, but the move has been indefinitely delayed due to logistical and construction problems. Iraq is an extremely dangerous hardship post with near daily insurgent mortar attacks on the fortified Green Zone where the embassy is located. The U.S. military has quietly but repeatedly complained that its forces and other Defense Department personnel have been pressed into service in jobs that should have been filled by State Department personnel. In particular, Defense Department employees and service members were forced to fill spots on provincial reconstruction teams for months because the State Department could not get personnel there. Military officials have complained that other federal agencies — including State, Commerce and Agriculture — aren't moving quickly enough to fill critical needs in Iraq. Those agencies, they argue, have the expertise to help Iraqi business people and farmers get back to their jobs and improve the economy.