If Russia wants to force Europe’s attention away from Ukraine, it could make trouble in the Balkans.

The Balkans are vulnerable to Russian meddling if President Vladimir Putin wants to put pressure on the European Union, a top Bulgarian foreign-policy expert warns.

Writing in the Financial Times , Ivan Krastev, who chairs the Center for Liberal Strategies in Sofia, Bulgaria and is a founding board member of the European Council on Foreign Relations, argues that if Putin seeks to regain the initiative in his standoff with the West, the Balkans would be a “likely hotspot.”

As well as being the EU’s backyard, the Balkans are the underbelly of Brussels’ diplomacy. Their banking systems are fragile. If businesses with large deposits and Russian connections were suddenly to pull their money out, the result could be widespread insolvency and with it civil strife. Pro-Western governments would teeter. This is the place to apply pressure, if Moscow wants to make Europeans feel uncomfortable.

Russia certainly does not “fantasize” about bringing countries like Albania and Bosnia into its sphere of influence, writes Krastev. The Balkan states trade far more with Europe than they do with Russia and those that aren’t in the European Union yet still hope to join the bloc.

But Russia does have influence, especially in Bosnia and Herzegovina as well as Serbia, to the point that German Foreign Ministry experts said last year they feared Putin could try to prevent the European Union from expanding in the region.

Russia has historically looked upon the Orthodox Christian and Slavic Serbs as a brotherly nation. Famously, it entered World War I in 1914 to defend Serbia against the Austro-Hungarian Empire and its German ally.

Like many countries in Eastern Europe, Serbia is completely dependent for natural gas on Russia. It was also a partner in Russia’s South Stream pipeline until Putin canceled the project late last year, citing European opposition.

During a visit to Belgrade in October, where he attended Serbia’s Liberation Day ceremonies, Putin reiterated his country’s opposition to Kosovo’s independence. All but five European Union member states have recognized the largely ethnic Albanian Republic of Kosovo. Serbian president Tomislav Nikolić, in turn, pledged not to bow to European pressure and join sanctions against Russia for its annexation of Ukraine’s Crimean Peninsula.

Bosnia might be more vulnerable to Russian machinations, given the country’s ethnic divisions. The German Foreign Ministry warned Russia was engaging in “public diplomacy with clear pan-Slavic rhetoric” there.

German agriculture minister Christian Schmidt told Der Spiegel in November, “One gets the impression that Russia is trying to gain influence over all of Bosnia-Herzegovina via the Serbian partial republic Srpska.”

Elmar Brok, a German conservative who chairs the European Parliament’s Committee on Foreign Affairs, told the same magazine, “Putin’s goal is to exert so much pressure on Balkan states that they either back away from EU membership or that, once they become members, influence EU resolutions in a pro-Russian manner.”

Perhaps seeking to stave off such a prospect, German chancellor Angela Merkel convened a meeting of Balkan leaders in Berlin last August and called for “speedy progress” in their countries’ accession to the European Union. “Slovenia and Croatia are already EU members,” she said, “and others have made quite considerable progress.”

Corruption and the risk of political instability nevertheless remain high in some Balkan states and nearly all have unresolved ethnic conflicts stemming from the violent breakup of Yugoslavia in the 1990s, making their admission to the European Union problematic.

Those same factors could make it easier for Russia to instigate a “controlled crisis” in the region, according to Krastev — which would force the West’s attention away from Ukraine and possibly divide Europe between countries that have little desire to expand the union further into the Balkans anyway and those that fret about where Russia’s aggression will end.