Ibrahim Kalin, spokesman for President Recep Tayyip Erdogan, said the display served as a propaganda tool for the PYD, the Syrian affiliate of the PKK, which is listed as a terrorist group by Turkey, the EU and U.S.

“It is unacceptable to make propaganda -- under the roof of European Parliament -- about a terror group which targets Turkish citizens every day,” Kalin told Anadolu Agency.

“We have difficulty understanding what the European Parliament is aiming at by polishing an organic extension of the PKK, which is listed as a terror group by the European Union.”

He said that if the event had been staged because the PYD is fighting Daesh in Syria “we advise them to open exhibitions on Nusra Front, Hezbollah and the bloodstained Assad regime.”

The exhibition features around 30 photographs showing PKK, PYD and YPG terrorists in northern Syria.

In one image, crowds carry a photograph of PKK leader Abdullah Ocalan, who was convicted of terrorism and treason in 1999 and is currently serving a life sentence.

Kalin said that Turkey saw no difference between terror groups such as the Nusra Front, Daesh, the PYD or PKK.

The photographs were taken by Austrian anthropologist Thomas Schmidinger and the Brussels exhibit is hosted by Josef Weidenholzer, vice-president of the parliament’s Progressive Alliance of Socialists and Democrats.

The pictures, which purport to represent “important figures and historical events in the development of Rojava” -- a name given to regions of northern Syria -- will be exhibited until July 15, according to Weidenholzer’s website.

Turkey has repeatedly criticized such displays as serving to promote terrorism.

In March -- prior to the Brussels attacks that killed 32 people -- the Belgian government allowed PKK supporters to pitch tents near the EU Council building on the eve of a Turkey-EU summit.

Turkish Foreign Minister Mevlut Cavusoglu criticized Belgium for showing double standards in tolerating terrorist groups, saying they should be treated in the same way as Daesh.

Terror organizations such as the PKK and the far-left Revolutionary People's Liberation Party-Front (DHKP-C) are active in Belgium and several PKK figures reportedly live in the country. There are also pro-PKK TV channels and last month Turkish officials protested about YPG flags hanging in the European Parliament.

Anadolu Agency