SKOPJE, North Macedonia — A top U.S. diplomat for Europe says delays in European Union accession talks with Albania and North Macedonia are helping adversaries of the West advance their geopolitical ambitions.

“There is much work to do,” Matthew Palmer, a deputy assistant secretary of state for Europe and Eurasia, told a conference Thursday in the resort town of Ohrid in North Macedonia.

“As our geopolitical competitors aggressively seek to undermine U.S.-EU credibility, and the region itself doubts the integrity of our collective commitment, the stakes for really advancing that work continue to grow.”

He did not name the adversaries, but United States officials have repeatedly referred to Russia’s competing influence in the region.

North Macedonia’s EU accession effort has been held up by a dispute with neighboring Bulgaria over the origin of the country’s language — a spat that has also indirectly hurt Albania’s push to join the bloc.

Balkan countries that have not yet joined the EU are at different stages of the membership process, with Serbia and Montenegro the most advanced. Palmer urged the region’s leaders to press ahead with difficult reforms required for eventual membership.

“They must work constructively to resolve difficult political issues internally and with neighbors, to strengthen their multi-ethnic democracies and judiciaries, and move towards a more prosperous, integrated future,” he said.