A bomb exploded Monday at a Turkish-American friendship association in a southern city hosting U.S. aircraft supporting war efforts in Iraq and Afghanistan, and four Turks were injured, authorities said.
There was no immediate claim of responsibility. Turkish Islamic militants linked to al-Qaida have been planning attacks on U.S. targets in Turkey. Leftist and Kurdish militants also are active in the country.
The injured, including three women, were hospitalized with injuries not considered life-threatening, the police said.
The explosion occurred in the hall of a building in downtown Adana. The city, about 280 miles south of the capital, Ankara, is home to Incirlik Air Base, which hosts 10 U.S. military refueling aircraft.
The U.S. Embassy in Ankara confirmed the explosion but could not say what caused the blast. A U.S. consulate also is located in Adana.
Al-Qaida-linked Turkish militants carried out a series of suicide bombings in Istanbul in November 2003, killing some 60 people.