The situation between both nations deteriorated further in early spring, when Berlin banned Ankara's pre-referendum rallies in Germany. At the same time, Turkey stalled the visit of a delegation of German lawmakers to the Turkish Incirlik airbase, which stations German soldiers.
"There are a range of opportunities that we can offer Turkey in the field of cooperation in the interests of Turkey. Think about the modernization of [European Union-Turkey] Customs Union. But this has a condition: Turkey should honor its legal obligations and, first and foremost, release the German citizens, who against their will and, in our firm belief, in violation of Turkish laws, are detained in Turkey both in the penitentiary institutions and outside them," the minister said at a press conference, adding that it is a "central condition."
Gabriel added he saw no opportunity to implement further proposals without the release of the German nationals.