The four NATO member countries in the Western Balkans expressed support for Ukraine and condemned Russia on Monday after a meeting in Bulgaria's capital.

The premiers of Bulgaria, Romania, Montenegro, and North Macedonia attended NATO's Multilateral Business Union meeting organized by Prime Minister Kiril Petkov in Sofia.

Macedonian Prime Minister Dimitar Kovacevski said the meeting sent another strong message of unity and solidarity with Ukraine.

He said its participants "remain firm in condemning the war in Ukraine as an illegal and illegitimate invasion of Russia."

"We condemned Russia's military aggression," added Kovacevski, asserting that the war in Ukraine "created a new reality in all sectors," including commodities and energy.

Romanian Prime Minister Nicolae Ciuca underlined that Russia's actions harmed security in the region, making cooperation among countries more important.

"Russia is the greatest threat to our security," said Ciuca. He added that the war had also increased the significance of NATO's eastern flank.

For his part, Montenegro's Prime Minister Zdravko Krivokapic stressed that the Balkans were is no longer a powder keg ready to explode into conflict.

"We remember the battle in Old Yugoslavia very well," he said, underlining that the countries in the region would "never repeat" such a war.

The leaders also discussed liquefied natural gas supplies through Turkiye and Greece, the alternative use of existing pipelines, and the construction of transport corridors in the region.

Two main corridors were on the agenda, according to Bulgaria's Petkov, who said one of these, dubbed Corridor No. 8, would have one end in the Montenegrin capital Podgorica, moving on to Durres, Albania; Skopje, North Macedonia; Sofia; Dimitrovgrad, Serbia; and Varna, Bulgaria.

The other corridor being discussed would pass through Alexandroupolis in Greece, Burgas and Varna in Bulgaria, and Constanta in Romania.