Martin Erdmann, Germany's ambassador to Ankara, was invited for talks at Turkey's Foreign Ministry concerning a "consular case" on Wednesday, confirmed the German Foreign Ministry.

Turkish media and the Cologne daily newspaper "Express" reported earlier that the ambassador had been summoned to the talks - a formal step, which would be a more severe diplomatic signal than merely an invitation.

The latest diplomatic spat between Berlin and Ankara concerns a senior Turkish lawmaker with Erdogan's ruling AKP party and the Cologne-Bonn airport. Aysenur Bahcekapili, deputy speaker for the Turkish parliament, was held for a short time by police at the airport due to missing papers.

On December 1, Bahcekapili wanted to travel to Turkey, but provided provisional papers that did not show her diplomatic status, North Rhine-Westphalia police confirmed to news agency DPA. The police, therefore, contacted the Turkish consulate to review her status.

"The whole process lasted a maximum of 45 minutes," the police spokesman said.

Turkish President Recep Tayyip Erdogan said Bahcekapili's passport had been stolen during her trip to Germany and procured temporary papers from the embassy but was still prevented from leaving.

During a speech earlier on Wednesday, Erdogan demanded steps be taken against the airport staff. He said Turkey would "retaliate in kind" against German lawmakers if the officers involved were not investigated.

Addressing Germany in his speech, he said: "You are receiving terrorists as guests in your country, but you let the deputy speaker of the Grand National Assembly and her delegation wait for hours at the door."

Relations between Turkey and Germany have become increasingly strained over a series of events, including Berlin's criticism of mass arrests in Turkey following the attempted coup in July and Ankara's treatment of the media. Turkey, on the other hand, accuses Germany of being a safe haven for the Kurdish militant PKK group.

rs/gb   (dpa, Reuters)