The United States has warned its citizens of a "possible terrorist threat" in Turkey.
"The US government has received unconfirmed and fragmentary information that suggests unknown terrorists may be planning to conduct a terrorist incident in southeast Turkey against official US government facilities or personnel," the State Department said.
The State Department said the Turkish government had already taken "all prudent measures" to protect against the potential threat.
Turkey is expected to play a key role should the United States go to war with neighbouring Iraq.
Incirlik is used by US and British aircraft as a base to patrol the no-fly zone over northern Iraq that was set up after the 1991 Gulf war to prevent Baghdad from attacking the Kurds. It could play an important role in any conflict against Baghdad.
