Supporters of Turkish President Tayyip Erdogan wave Turkish flags during a pro-government protest in Cologne, Germany July 31, 2016. [Photo/Agencies]

ANKARA - Turkey on Monday summoned the charge d'affaires at the German Embassy, a day after German authorities prevented Turkey's President Recep Tayyip from addressing by a video link a rally staged by his supporters in Cologne, Turkish media reported.

Tens of thousands of Turks living in Germany gathered in Cologne on Sunday condemning the July 15 coup attempt.

Germany's highest court, Federal Constitution Court, had upheld a ban on Erdogan's broadcasting a message to his supporters at the rally.

German police said the measure was taken for "security reasons," while a local court agreed on the decision and issued the ruling.

Turkey's Deputy Prime Minister Numan Kurtulmus said on Monday that further actions will be carried out in response to the ban.

"This is a double-standard by German judicial authority," he said, describing the move as a "ban on the freedom of expression."

Turkey demands that Germany extradite supporters of Fethullah Gulen, a US-based cleric Ankara accused of masterminding the failed coup.

The German court's decision heightened tensions between Germany and Turkey at a time when Ankara is stepping up its crackdown on suspected coup plotters.

This is the second major incident marring bilateral relations in two months.

On June 2, Turkey recalled its mission chief after the German parliament adopted a resolution recognizing the 1915 killing of Armenians as "genocide."