Two suspects in the killing of U.S. ambassador to Libya Christopher Stevens have been detained at Istanbul's Ataturk Airport, Turkish broadcaster Kanal D reported on its website on Friday.

It said Turkish police held the two suspects, described as Tunisian citizens, as they tried to enter the country with fake passports.

Police in Istanbul declined comment on the report.

Stevens was one of four Americans who died when Islamist gunmen stormed the Benghazi consulate last month.