German public broadcaster SWR says one of its reporters has been detained upon arrival at Istanbul airport.

SWR says Cairo-based TV correspondent Volker Schwenck was given no reason for his detention early Tuesday. It says he is being held in the airport's deportation room.

Schwenck, who had planned to travel to the Syrian border to interview refugees, posted a picture on Twitter of a document titled "Inadmissible Passenger Notification Report."

He tweeted: "Final stop Istanbul. Entry to Turkey denied. There's a note with my name. I'm a journalist. A problem?"

SWR is part of the ARD network, one of two main public broadcasters in Germany. The other, ZDF, has become embroiled in a row with Turkey over a satirical program featuring a crude poem about Turkish President Recep Tayyip Erdogan.