Zurich on Wednesday asked the Swiss government to cancel a planned visit by the Turkish foreign minister to the canton over security concerns, after several local authorities in Germany blocked rallies by Turkish ministers.

"I've sent a letter to Bern, to (Swiss Foreign Minister Didier) Burkhalter, stating that we want them to take measures that the planned event in Zurich on Sunday would not happen," Urs Grob, communications director at Zurich's cantonal security directorate, told AFP.