Updated

Turkey's president has hit out at the head of Germany's intelligence service for suggesting that Berlin is not convinced U.S.-based cleric Fethullah Gulen played a role in last year's failed coup.

Recep Tayyip Erdogan on Friday accused the BND foreign intelligence chief Bruno Kahl of making the remarks on behalf of Germany's leaders, who he said backed Gulen's movement.

Kahl told Der Spiegel magazine that Turkey tried to "convince us on a number of different levels. But they haven't yet been successful."

Gulen denies orchestrating the coup attempt. Turkey is seeking his extradition from the United States.

Erdogan's words come at a tense time in Turkey's ties with Germany and the Netherlands following restrictions imposed on Turkish ministers wanting to campaign there for a referendum on ushering in a presidential system.