Germany's foreign minister interrupted his vacation on the North Sea to return to Berlin to deliver the most strongly worded statement yet against Turkey's imprisonment of German journalists and human rights activists.

"We want Turkey to be a part of the West, or at least remain in its current position, but it takes two to tango," Sigmar Gabriel at a press conference in Berlin. "I cannot make out any willingness on the part of the current Turkish government to follow this path with us. For that reason Germany is forced to reorient its Turkey policy. The first consequences will be new travel advisories for German citizens in Turkey."

Gabriel said that Germans traveling to Turkey were incurring "risks," and the ministry website recommended Germans should exercise "heightened caution" when visiting Turkey since "consular access" to Germans detained in Turkey had been "restricted in violation of the obligations of international law."

Read more: Germany reviews export credits to Turkey over blacklisted firms

Gabriel said that the measures were being taken after consulting with both conservative chancellor Angela Merkel and Social Democratic chairman and chancellor candidate Martin Schulz. Although they stopped short of a travel warning against Turkey, they do represent an increased frostiness between the two countries.

'Obviously unfounded accusations'

The re-calibration of Germany's Turkey policy came after a court in Istanbul ordered six human rights activists, including Peter Steudtner from Berlin, to investigative custody on Tuesday. Turkey accuses them of supporting terrorism.  Gabriel specifically mentioned Steudtner.

"These accusations are obviously unfounded and have simply been dragged out irrationally," the foreign minister said, adding that Steudtner had taken no position on current Turkish politics and was quite possibly present in the country for the first time.

The Amnesty International representative was arrested earlier this month at a conference in Istanbul while teaching Turkish colleagues about IT security and non-violent conflict resolution. German journalist Deniz Yucel has been held in investigative custody since late February. Seven other Germans are also currently in such custody.

Gabriel said that Germany had showed patience in the ongoing row with Ankara and hadn't responded to incendiary comparisons between the Federal Republic and Nazi Germany. He said Berlin had tried to restart relations with Turkey, but had been "repeatedly disappointed."

"The government and the coalition parties will be discussing further consequences," Gabriel said, adding that a range of financial sanctions were also under consideration.

Access to German detainees

On Wednesday, Turkey's ambassador to Germany was summoned to the German Foreign Ministry and warned that Berlin does not accept the detention of its citizens. German Justice Minister Heiko Maas has said that Germany must take a tougher stance towards Turkey, but cautioned that diplomatic relations also had to be maintained.

"We have to keep in mind that German citizens are sitting in Turkish jails, and we need access to them," Maas told the DPA news agency. "I think it would be a mistake right now to give Turkey any arguments to deny us that access."

Turkey has accused Germany of interfering in its internal affairs. There has been speculation that Erdogan is using the German detainees essentially as hostages in an attempt to force Berlin to deport Turkish citizens in Germany whom Ankara considers terrorists.

Other German politicians have called for a range of measures to punish Turkey from general economic sanctions to a cancellation of the deal between the EU and Turkey on refugees.

Turkish non-delight

The Turkish government criticized Gabriel's remarks and the announced change in the German position. Turkish Foreign Minister Mevlut Cavusoglu meanwhile reacted by accusing Germany of harboring terrorists:

Cavusoglu said on Twitter said on Twitter that "As a country providing shelter to PKK and FETO terrorists in its own territory, statements by Germany are just double standards and unacceptable," referring to the outlawed, militant Kurdistan Workers Party (PKK) and the religious-inspired network of US-based cleric Fethullah Gulen that Ankara blames for the July 15, 2016 failed coup.

Erdogan's spokesman, Ibrahim Kalin, meanwhile said: "We strongly condemn statements that German citizens who travel to Turkey are not safe and that German companies in Turkey should have hesitations and concerns."

The Chairman of the Commission for Foreign Affairs Taka Ozhan, a member of Erdogan's AKP party, repeated Turkish accusations that Germany is harboring Turkish citizens who are trying to overthrow the government – in particular, Kurdish separatists and members of the Gulen movement.

"What we're seeing in Germany at the moment is a crisis of principals," Ozhan said in a statement to Deutsche Welle's Turkish division. "The question is whether terrorism is supported or not…The Terrorists think 'Once we get to Germany, we're home safe.' That has to change."

The number of Turks applying for asylum in Germany dramatically increased last year amidst a government crackdown after the failed Turkish coup on July 15, 2016. Since then, tens of thousands of people have been arrested and more than 100,000 have lost their jobs in Turkey.