BRUSSELS — The European Union on Tuesday warned Bulgaria that it risks undermining security in the Balkans and elsewhere in Europe if it continues to block EU membership talks for North Macedonia.

EU leaders gave Albania and North Macedonia the green light in March to begin accession negotiations but no date was set for the talks to start. Now Bulgaria is insisting that North Macedonia formally recognize that its language has Bulgarian roots and stamp out what it says is anti-Bulgarian rhetoric. 

In late November, some 2,000 protesters staged an opposition rally in North Macedonia to demand the resignation of the country's Social Democrat prime minister, Zoran Zaev, accusing his government of being too conciliatory to neighboring Bulgaria.

German European Affairs Minister Michael Roth, whose country holds the EU's rotating presidency, said that his country is doing all it can to end the standoff, but EU diplomats are doubtful that a breakthrough will be made anytime soon.

"Anything else would be a very severe political mistake at the expense of stability and security in the western Balkans, and that ultimately would massively endanger the security of Europe as a whole — and all should be aware of that," Roth told reporters.

North Macedonia and Albania were actually meant to start EU membership talks last year, but France blocked them, saying the process of joining the 27-nation bloc should be reformed first. The logjam was freed after the European Commission revised the process for holding their talks.

The prospect of EU membership has long been seen as an incentive driving democratic, political and economic reforms in the volatile Balkans region.

North Macedonia, previously known as Macedonia, has been a candidate for EU membership since 2005, but a long-running dispute with Greece over the country's name was the biggest obstacle to accession negotiations. 

The two neighbors struck a deal for Macedonia to rename itself North Macedonia in exchange for Greece dropping its objections to the country joining the EU. The German EU presidency is frustrated that another debate over history, this time with Bulgaria, has suddenly reared its head.

Countries must negotiate 35 "chapters," or policy areas, to join the EU. The chapters are wide-ranging and include financial, agriculture, transport, energy, social and justice policy, among other areas.

The process can be drawn out. For example, Croatia, which joined the EU in 2013, started its negotiations at the same time as Turkey, which is unlikely to become a member anytime soon.