The US military command in Europe has ordered American forces across Turkey to take maximum protective measures following the attempted military coup there, a US military source said Saturday.
The US military has around 2,200 service members and civilian employees in Turkey, which is a NATO member and a crucial regional partner for Washington.
About 1,500 of them are stationed at Incirlik, the military base in southern Turkey from which American warplanes have launched bombing missions against the Islamic State group.
US forces in Turkey were now at the "Delta" force protection level, such as is invoked when a terrorist attack is taking place or appears imminent, the American defense official said.
"We are firmly committed to making every possible effort to ensure the safety and security of our service members, civilians, their families and our facilities," the official said.
At the Delta level, all non-essential activities are suspended and all resources placed in defensive positions in case of attack.
An American military official had confirmed late Friday that operations against the Islamic State group were continuing from Incirlik despite the attempted coup.