ANKARA (AFP) - Turkey on Saturday called in Germany's ambassador to Ankara as tensions flared between the two countries following Turkey's violent crackdown on protesters.

Berlin and Ankara on Friday both summoned each other's ambassadors in tit-for-tat moves as fresh obstacles also emerged over the past week linked to Turkey's bid to join the European Union.

News channel NTV said Ambassador Eberhard Pohl spent over an hour in his meeting with foreign ministry undersecretary Feridun Sinirlioglu, but that neither of the two sides had wished to comment on the discussion afterwards.

On Monday, German Chancelor Angela Merkel said Turkey's violent crackdown on demonstrators protesting against Prime Minister Recep Tayyip Erdogan's Islamic-rooted government had been "much too harsh".

What began as a peaceful protest against plans to demolish Istanbul's Gezi Park, one of the city's last large green spots, turned violent on May 31 when police used tear gas and water cannon to disperse demonstrators.

Mr Erdogan has faced international condemnation over his handling of the crisis, which has left four dead and injured thousands of demonstrators, tarnishing Turkey's image as a model of Islamic democracy.

Germany's views carry particular weight as around three million people with Turkish roots live in Europe's top economy, which is Turkey's biggest trading partner.

On Friday, Turkish European Union Affairs Minister Egemen Bagis warned Germany of consequences unless Ms Merkel retracted her comments.

The spat also comes as European diplomats say both Germany and the Netherlands have expressed "reservations" against opening a new negotiating chapter with Turkey next week in Ankara's bid to join the EU.

But a German foreign ministry spokesman has insisted that Ankara's response to the demonstrations had no direct bearing on the EU accession talks.

Also on Saturday, the foreign ministers of the two countries met on the sidelines of a Friends of Syria meeting in Doha to discuss Turkey's relations with the EU.

According to a brief statement released by Germany's foreign ministry, the meeting between Guido Westerwelle and his Turkish counterpart Ahmet Davutoglu was held in a "constructive and amicable atmosphere," where the two diplomats enjoyed "an intensive exchange of opinions as partners and friends."

Meanwhile, some 80,000 people rallied against Erdogan's government in the German city of Cologne.