Turkish Foreign Minister Mevlüt Çavuşoğlu has reacted to a Thursday statement by Foreign Minister of Germany Sigmar Gabriel concerning the arrest of German human rights consultant and activist Peter Steudtner, saying Turkey will not submit to threat and blackmail.

“It should be known that threats and blackmail against Turkey will not yield any results,” said Çavuşoğlu during a visit to the Turkish Republic of Northern Cyprus (KKTC) on Thursday.

Recalling that ‘Gabriel has asked for the release of those who supported terror in Turkey and were arrested for espionage, and even gave Ankara a deadline,” Çavuşoğlu said: “He expresses this demand in an approach and tone that challenge the Turkish judiciary and are not compatible with diplomatic courtesy.”

“Germany knows very well that Turkey does not submit to any threat or blackmail.”

German Foreign Minister Gabriel on Thursday said Turkey long ago planned the arrest of German human rights consultant and activist Steudtner, who was put in pre-trial detention on Tuesday.

Six human rights activists, including Amnesty International’s (AI) Turkey Director İdil Eser and Steudtner, who were detained on July 5 during a workshop at a hotel on İstanbul’s Büyükada, were put in pre-trial detention by an İstanbul court on Tuesday.

“The arrest of German activists is an attempt to silence critical voices, and the arrest of German human rights activist Peter Steudtner was planned long ago,” Gabriel said, as reported by BBC Turkish on Thursday.

Underlining that Steudtner had no relation with Turkish politics and that it was probably his first visit to the country, Gabriel criticized the decision to arrest and said: “These accusations are obviously unfounded and have simply been dragged out irrationally.”

The German Foreign Ministry issued a warning to its citizens planning to visit Turkey.

“Until now there was guidance for certain groups but we’re saying that now applies to all German citizens, not just for those with certain jobs. …. Everyone can be affected. The most absurd things are possible,” said Gabriel.

In addition to Steudtner, German journalist Deniz Yucel and seven other Germans are currently in custody in Turkey.

Underlining a serious crisis of confidence between Berlin and Ankara in a statement on Thursday, Turkey’s Foreign Ministry said: “Today’s remarks by German Foreign Minister Sigmar Gabriel were the latest and an unacceptable example of this one-sided, distorted approach.”

Turkey has accused Germany of engaging in “diplomatic rudeness” and “double standards,” saying it supports members of terror groups and hinders their trials.

Turkish President Tayyip Erdoğan is allegedly detaining German nationals to force the deportation from Germany of Turkish asylum seekers, who Erdoğan accuses of having mounted a botched coup attempt on July 15, 2016.