EU mulls visa bans on Balkans extremists stirred up by Moscow

"Many far-right movements in the Western Balkans have a strong aversion towards Nato and the European Union," the memo, drafted by the new Czech EU presidency and seen by EUobserver, said.

"One reason for the increasing distrust towards the West is the strong relationship Russia has built up with the Orthodox Christian populations in the region. Russia presents itself as the protector of certain nations in particular, but also of Orthodox Christian groups in the Western Balkans," it said.

In the past, EU concerns centred around jihadist foreign fighters returning to the region from the Middle East.

But the war in Ukraine has seen "some local followers of the far-right left to fight in the ongoing conflict in Ukraine, most probably on the Russian side", the Czech memo said.

It painted a complex picture of the problem, which involves "radical football fans, or radical followers of various pan-Slavic, nationalistic" movements.

"It is often very difficult to differentiate between the far right and the far left in the Western Balkans," the memo said.

Some groups, such as Blood and Honour and Combat 18, who attack migrants and foreigners in general, are also "still active".

And taken together, they create an "increasing threat for the region" as well as for internal EU security.

"Have you noticed any links in individual EU member states between 'local' right-wing extremists and the Western Balkan far right?," the Czech presidency asked fellow member states.

"Are there any signs of growing influence by Western Balkan far-right organisations on the Balkan diaspora in member states?", it added.

The memo said jihadists still posed the greatest threat in terms of large-scale loss of life.

But it pointed out that "ethno-nationalist" attacks, even if they were on a smaller scale, risked aggravating political instability in a region that not long ago fought a series of bloody ethnic conflicts.

"The threat of large-scale terror attacks inspired by VRWE [violent right-wing extremist] ideologies is arguably quite low," two experts from Rusi, a London-based think-tank, said in a recent study cited by the Czechs in their memo.

"However, even small-scale acts of violence could act as the ignition point for regional destabilisation," the Rusi study warned.