German Vice Chancellor and Foreign Minister Sigmar Gabriel | Kay Nietfeld/AFP via Getty Images Turks in Germany ‘belong here,’ says foreign minister Sigmar Gabriel struck reassuring tone in open letter to Turkish citizens living in Germany.

FRANKFURT — Turks living in Germany are welcome and "belong here," said the country's foreign minister Sigmar Gabriel in an open letter designed to reassure citizens alarmed at the country's soured relations with Turkey.

President Recep Tayyip Erdoğan's moves to suppress democracy and crack down on political opponents have brought condemnation from Germany and led to an escalating row between the countries. Erdoğan also prevented German politicians from visiting troops based at a Turkish airbase.

"No matter how difficult political relations between Germany and Turkey are, one thing remains clear: You, people of Turkish roots in Germany, belong here — whether with or without a German passport," Gabriel said in a letter published in Germany's largest tabloid Bild in both German and Turkish.

Speaking for the German federal government, Gabriel said that Germany has always worked for good relations with Turkey. "But now innocent German citizen are thrown into prison. As the German government we cannot simply stand by and watch. We have to protect our citizens," he asserted.

Earlier this week, Germany's head of domestic intelligence said Turkish agencies were targeting Erdoğan's opponents in Germany. German Finance Minister Wolfgang Schäuble also compared Turkey's actions in detaining six human rights activists, including a German, to the authoritarian former communist East Germany.