The U.S. State Department has ordered family members of consulate employees in Istanbul to leave the country.
The decision is “based on security information indicating extremist groups are continuing aggressive efforts to attack U.S. citizens in areas of Istanbul where they reside or frequent," the State Department said on October 29.
It said the order applies only to the U.S. Consulate General in Istanbul, which remains open and fully staffed, not to any other U.S. diplomatic posts in Turkey.
Last week, the State Department advised U.S. citizens to "carefully consider the need to travel to Turkey."
There is also a long-standing warning against travel to the country's southeast.
Anti-American sentiment runs high in Turkey, a NATO ally, where emergency laws have been in effect since a failed coup attempt in July.
The country is also fighting a renewed insurgency by Kurdish separatists and is dealing with the fallout of the war in neighboring Syria, including attacks by the Islamic State group.