The EU has made a "historic mistake" that risks destabilising the Balkans, senior officials warned Friday, after a handful of countries led by French President Emmanuel Macron again blocked membership talks for North Macedonia and Albania.

There was widespread frustration and disappointment, particularly among eastern European countries keen to broaden the EU club, at the failure of the 28 leaders to agree to start formal accession negotiations with Skopje and Tirana.

Leaders were deadlocked after some seven hours of heated backroom wrangling at a Brussels summit, with France alone in rejecting North Macedonia but joined by Denmark and the Netherlands in refusing Albania.

"It's a major historic mistake and I hope it will only be temporary and won't become engraved in the collective memory as a historic mistake," European Commission chief Jean-Claude Juncker said.