BERLIN, July 24 (Xinhua) -- German President Frank-Walter Steinmeier offered unusually strong criticism of the Turkish government during an appearance on TV channel ZDF on Sunday night.
According to the German president, the last remainders of criticism and opposition in Turkey were now being "persecuted, imprisoned and silenced."
"We cannot accept this," Steinmeier said.
On Sunday, head of the Christian Social Union Horst Seehofer and Social Democrat leader Martin Schulz both called for placing financial pressure on Turkey in a surprising show of cross-party unity.
Seehofer demanded the freezing of all payments which Turkey is due to receive from the European Union (EU) as an accession candidate until 2020. This would amount to roughly 4 billion euros. Schulz supported the initiative of his political rival which he described as a "concrete measure which can be taken immediately."
Turkish President Recep Tayyip Erdogan reacted with dismay to such threats, rejecting German meddling into the interior affairs of his country.
The Turkish government had previously caused outrage in Germany last week by arresting German human rights activist Peter Steudtner.
The German Foreign Office reacted by warning tourists to exercise "heightened caution" on vacation in Turkey while Finance Minister Wolfgang Schaeuble likened random arrests in Turkey to practices witnessed in former East Germany.
Additionally, German officials said they would re-assess financial aid Turkey receives both from Germany and the EU.
Steinmeier voiced the belief that it was important for the German government to send clear signals to Turkey which he described as a "question of self-respect for our country." It had also been necessary for the Federal Government to address the 3 million residents of Turkish origin who live in Germany.
Earlier, German Foreign Minister Sigmar Gabriel addressed that group in an open letter published in German and Turkish languages in which he had sought to express Germany's appreciation for their contribution as citizens.
"The friendship between Germans and Turks is a great treasure," the letter read.
According to a recent survey, the vast majority of Germans are unhappy with their government's policy towards Turkey. Some 76 percent of respondents said that officials were too tolerant of Erdogan's behavior.
Speaking to the Bild newspaper on Monday, Schaeuble accused Erdogan of endangering the "century-old partnership between Turkey and Germany."
"We cannot allow ourselves to be blackmailed," Schaeuble said.
German-Turkish relations have been in a near-constant state of crisis since a military coup failed to unseat Erdogan in July 2016.
Ankara has rejected Berlin's criticism that it engaged in an excessive crackdown on political opponents in response to the coup and is resentful towards its German NATO partner for allegedly granting asylum to Turkish revolutionaries.
Figures released recently by German Federal Office for Migration and Refugees suggest that the number of Turkish asylum seekers in Germany has risen dramatically since July 2016.
There is also a long-standing spat between Berlin and Ankara over attempts to prevent Turkish politicians from holding campaign rallies in Europe. Hoping to win support among Turkish migrant communities for a controversial constitutional referendum which ultimately passed in April 2017, Erdogan and members of his AKP party ran up against heavy opposition in several European capitals.
Turkey retaliated by banning German parliamentarians from visiting their country's armed forces stationed at the Turkish military base of Incirlik and Konya from where they were participating in the international military effort against the so-called "Islamic State".
In June, German lawmakers voted to transfer troops from Turkey to a new base in Jordan after several attempts to defuse the diplomatic crisis failed.
