The EU's envoy to Turkey, Hansjoerg Haber, has resigned after less than a year in the position, according to his office.
The EU delegation in Ankara confirmed that Haber was leaving his post on Tuesday, without giving any reason.
Turkey was Haber's first assignment as a German diplomat between 1993 and 1996, and he returned as European Union ambassador to Turkey in September 2015.
The resignation comes at a sensitive time in EU-Turkish relations as the bloc recently brokered a deal with Turkey to curb the influx of refugees entering Europe.
Ankara gained visa-waivers for its citizens to travel in Europe in exchange for stemming the flow of people making the journey to Greece by boat.
Turkey, which borders Syria, is home to more than two million refugees from Syria, but also from Iraq, Afghanistan, and other Middle Eastern and Asian states.
Germany took in nearly a million refugees in 2015 but the mass movement of people from mainly Muslim countries has incurred criticism from Chancellor Angela Merkel's political opponents and led to the growth of far-right parties.
Source: AP And Al Jazeera