The EU voiced concern Thursday about "external influences" fueling division in the western Balkans, as Britain announced a summit to focus efforts on stabilising a key region vulnerable to Russian meddling.
"Today I can announce that the UK will lead the way by hosting the 2018 Western Balkans summit," British Prime Minister Theresa May said as EU leaders prepared to discuss the issue at a summit in Brussel.
"I will make clear my concerns about the potential for increased instability in that region and the risks that presents to our collective security," she said.
"In the light of the alleged Montenegro coup plot, I will call for us do more to counter destabilising Russian disinformation campaigns and raise the visibility of the Western commitment to this region," May added.
Montenegro authorities say Serbs acting at Russia's bidding tried to assassinate then prime minister Milo Djukanovic on election day on October 16 as part of a plot to destabilise the small country.
Montenegro hopes to become a NATO member later this year, a move considered by Russia to be a "provocation" and a threat to its own security.
The European Union has meanwhile established close ties with the region, holding out the prospect of economic aid and ultimately membership but progress has been slow, causing doubts to grow about the EU's commitment.
EU president Donald Tusk said separately that "tensions and divisions have got out of hand partly due to unhealthy external influences which have been destabilising several countries for some time".
"The EU remains ... fully committed to the stability and prosperity of the region. I want leaders to reconfirm the EU perspective for the Western Balkans," he said.
Germany held the first Western Balkans summit in Berlin in 2014, bringing together the former states of Yugoslavia and the international community to highlight the region's European future.
This year's meeting is in Rome.