Some US government employees from the US Embassy in Baghdad and its consulate in Erbil have been ordered to leave Iraq.
In a statement, the US State Department said: "Normal visa services at both posts will be temporarily suspended".
A US State Department spokesman said the decision to withdraw the staff was based on escalating tensions between Washington and Iran.
He, however, didn't give details on how many personnel were leaving.

Netanyahu orders deeper Israeli incursion into Lebanon
Blast in Myanmar village reportedly kills 55 and injures dozens more
US military says it turned away blockade runner trying to reach Iranian port
Two hundred hurt in post-game violence as Paris hails second Champions League triumph
Illegal mine collapses in China, killing five just days after Shanxi disaster