According to the Athens correspondent covering Greece, the Balkans and Cyprus, Thijs Kettenis, German police officers and quite possibly from other European countries as well, conduct passport checks on behalf of Frontex in Serbia to passengers coming from Greece.

Mr. Kettenis twitted a photo and commenting: “Didn’t know this also happens in non-EU countries on Balkan route”.

Belgrade Airport: passport check at gate for incoming passengers from Athens. By Serbian police and german Frontex officer. Didn’t know this also happens in non-EU countries on Balkan route pic.twitter.com/2mEYvEWEIJ

— Thijs Kettenis (@ThijsKettenis) May 10, 2018