The US ambassador to Iraq, Ryan Crocker, has defended the state department's decision to force diplomats to serve in the country.
Many positions are due to become vacant at the new Iraq embassy
Mr Crocker said diplomats who refused were "in the wrong line of business" and ought to put the nation's interests before their own personal safety.
On Wednesday, hundreds of US diplomats expressed their anger at the decision, calling it a potential death sentence.
The plan has been put forward because of a lack of volunteers for vacancies.
An attractive financial package is being offered as well as a generous leave allowance.
But the Baghdad embassy is considered a hardship posting due to security risks and because spouses and children must be left at home.
Speaking at a news conference in Dubai, Mr Crocker called Iraq the state department's "most important challenge" and said serving as a diplomat "does not mean you can choose the fight".
"It's not for us to decide if we like the policy or if the policy is rightly implemented," he said. "It's for us to go and serve, not to debate the policy, not to agree with it."
"You run a risk in Iraq. We try to manage and minimize the risk, but we cannot eliminate it entirely."
Mr Crocker then made it clear that diplomats who put their personal safety first were "in the wrong line of business".
"As we try to staff the embassy in Iraq, it is good for all our colleagues to remember that we took an oath to serve our nation worldwide when we joined the Foreign Service, just as the military swore an oath," he added.
Mr Crocker's comments come a week after the state department's human resources director, Harry Thomas, notified about 250 "prime candidates" that they had been selected for one of 48 one-year postings in Iraq.
American diplomats have been sent on forced assignments before - some had to take postings in some African countries in the 1970s and 1980s, and in 1969 an entire class of new Foreign Service officers was sent to Vietnam.