Chancellor Angela Merkel said Thursday that Germany must not allow Turkey to "grow more distant", despite a bitter row in which President Recep Tayyip Erdogan has likened her government to the Nazis.

"As difficult as everything is at the moment, as unacceptable as some things are, it can't be in our security and geopolitical interest that Turkey, a NATO partner after all, grows even more distant from us," she told parliament.

Merkel vowed to "work for German-Turkish relations, on the basis of our values and in all clarity".