Poroshenko faces new security crisis

President Petro Poroshenko confronted a fresh crisis yesterday as a deadly standoff continued between interior ministry units and armed Ukrainian ultranationalists in a western enclave near Hungary.

The EU-backed leader planned to convene his "military cabinet" of top generals yesterday to try and diffuse tensions between two forces vital to his bid to stamp out a separatist insurgency 1,000 kilometres away in eastern Ukraine.

The Pravy Sektor (Right Sector) nationalists played a small but instrumental role in three months of pro-European protests that eventually toppled the Russian-backed leadership in February 2014.

They then formed the heart of some of the best-equipped units to wage war against pro-Russian militias that overran parts of Ukraine's eastern industrial heartland in the wake of the Kiev revolution.

Interior ministry battalions are also at the forefront of the 15-month battle against the separatist fighters that has claimed more than 6,500 lives.

But mistrust between volunteer units and Ukraine's armed forces has been building as Poroshenko tries to follow through on a February peace deal whose terms -- including partial self-rule for the insurgents -- are anathema to the nationalists.

Pravy Sektor members also cast themselves as Robin Hood figures who defend the public against the corruption that has ravaged Ukraine's political establishment and police since the Soviet Union's collapse in 1991.

The weekend battles were sparked by Pravy Sektor's self-proclaimed attempt to prevent Hungary and Slovakia from being flooded with any more contraband cigarettes.