The European Union backs the European diplomats who attended a controversial trial of two Turkish journalists charged with espionage after their appearance was bitterly attacked by Ankara, an official said Wednesday.

The European Union backs the European diplomats who attended a controversial trial of two Turkish journalists charged with espionage after their appearance was bitterly attacked by Ankara, an official said Wednesday.

Turkey issued a protest on Monday over comments on social media made by some diplomats present at the trial last week of the opposition Cumhuriyet daily's editor-in-chief Can Dundar and Ankara bureau chief Erdem Gul.  

"EU diplomats regularly attend trials throughout the world as observers, in particular also in candidate countries," an EU spokesperson told AFP in an emailed statement.  
"This is thus part of their regular work in Turkey, a country committed to the highest democratic standards, in conformity with the European standards."

Turkey is a long-standing candidate to join the EU but its bid has long been held up by disputes on a range of issues including human rights.

Dundar and Gul face possible life terms on spying charges over a news report accusing President Recep Tayyip Erdogan's government of seeking to illicitly deliver arms bound for neighboring Syria.

The case has stoked concerns over media freedom in Turkey, ranked 149th out of 180 countries for liberty of the press by Reporters Without Borders in 2015.

Last Friday's trial was attended by top EU diplomats including the British consul general to Istanbul, Leigh Turner, who shared pictures including a selfie with a grinning Dundar, which drewire of Erdogan who accused diplomats of exceeding their power.

The EU official said "free, diverse and independent media constitute one of the cornerstones of a democratic society".

The United States, whose representatives were also present, has also said the diplomats' presence was "completely in keeping with standard diplomatic practice" and "darn sure" would not be the last time they made such an appearance.

"This was not only not the first time, but it darn sure won't be the last time that we observe these kinds of judicial proceedings," State Department spokesman John Kirby said Monday.

The Turkish court on Friday ordered the trial to be held behind closed doors for what it described as "national security" concerns. Kirby said Washington regretted this move.