Turkey refused on Friday to give permission to seven German lawmakers who were planning to visit German soldiers stationed at a NATO base in the central Turkish province of Konya, Berlin officials said.

The German parliament’s press office said last week that the seven Bundestag lawmakers were due to visit the base on July 17 in order to assess Germany’s participation in reconnaissance flights over Syria.

The tension between Germany and Turkey once again was on the rise after Germany did not allow Turkish President Recep Tayyip Erdoğan to address Turkish expats in Germany when he visited for the G20 summit.

In recent months, Turkey has strongly objected to European governments denying its officials permission to hold rallies or address expatriate citizens ahead of Turkey’s April 16 constitutional referendum.

Turkey did not allow German lawmakers to visit their soldiers stationed at İncirlik, due to controversial statements, mostly made by lawmakers from the socialist Die Linke party (The Left) who publicly announced their support to the PKK, which is listed as a terrorist organization by Turkey, the EU and the U.S.

Ahead of parliamentary elections in September, Angela Merkel’s coalition partner, the Social Democratic Party (SPD), took a surprise decision and demanded to withdraw German soldiers from İncirlik, in protest to Turkey’s stance.

Between 20 and 30 German troops are normally stationed at the base in support of NATO’s anti-Daesh operations.

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