European Commissioner Johannes Hahn said in Washington on Wednesday that the United States and European Union want to bring the Western Balkans into the EU.

Our shared goal on both sides of the Atlantic is to stabilize the region and bring all six Western Balkan countries into the EU based on established conditions. That’s in our geopolitical self-interest,” he wrote on his Twitter account from a meeting of the Atlantic Council.

He said that the expansion to the Western Balkans is a question of the EU’s credibility and added that Brussels has to meet its obligations in that regard.

Hahn warned that failure to meet obligations means loosing an advantage. “We have to be firm but fair,” he is reported to have said.