At least two people have been killed and nine wounded in gun battles between Ukrainian special forces and pro-Kremlin militias that threatened to scuttle the first international talks on the worst East-West crisis since the Cold War.
The clashes across the ex-Soviet state’s separatists eastern rust belt broke out a day after masked gunmen stormed a series of police and security service buildings in coordinated raids that Kiev blamed on the “provocative activities of Russian special services”.
The heavily Russified region has been riven by unrest since a team of Western-backed leaders rose to power in February on the back of bloody protests against the old regime’s decision to reject an EU alliance and look for future assistance from the Kremlin.
Russia has since massed around 40,000 soldiers along Ukraine’s eastern frontier and threatened to halt its neighbour’s gas supplies over unpaid bills – a cutoff that would impact at least 18 EU nations and threaten further retaliation against the Kremlin.
Saturday’s attacks were especially unsettling for both Kiev and Western leaders because of their remarkable similarity to events leading up to Russia’s annexation of Ukraine’s Crimea peninsula last month.
The balaclava-clad gunmen were armed with special-issue assault rifles and scopes most often used by nations’ crack security troops.
Many wore unmarked camouflage uniforms similar to those seen on the highly trained units that seized the Black Sea peninsula in early March. They also moved with military precision and cohesion.
But Russia denied any involvement. And it sternly warned Kiev late on Saturday that the use of force against pro-Russian protesters could ruin the chances of the two sides sitting down for US-EU mediated talks in Geneva on Thursday.
Ukraine’s Interior Minister Arsen Avakov announced the launch of an “anti-terrorist” operation in the eastern Donetsk region early on Sunday.
Crack units from Ukraine’s SBU security service first attacked an occupied police station in the eastern city of Slavyansk that was seized by about 20 militants on Saturday.
But Avakov admitted that his troops had to “regroup” after meeting stiff resistance and suffering casualties.
“There are dead and wounded on both sides. On our side – an SBU officer. The head of the SBU’s anti-terrorist centre has been wounded, as have four others,” Avakov wrote on his Facebook page.
“On side of the separatists – an unidentified number. The separatists have started to protect themselves using human shields.”
The local administration separately reported a series of heavy clashes on a highway linking Slavyansk with the region’s capital Donetsk to the south.
The Donetsk administration said one person was killed and four wounded in an “ongoing armed standoff” on a stretch of the road connecting Slavyansk and the town of Artemivsk.
The US State Department said John Kerry phoned his Russian counterpart Sergei Lavrov on Saturday to make “clear that if Russia did not take steps to deescalate in eastern Ukraine and move its troops back from Ukraine’s border, there would be additional consequences”.
Britain’s Foreign Office on Sunday said the wave of occupations of government buildings was “a dangerous escalation”.
“Assumptions that Russia is complicit are inevitable as long as Moscow does not publicly distance itself from these latest lawless actions.
NATO chief Anders Fogh Rasmussen also said he was “extremely concerned”.
“The reappearance of men with specialised Russian weapons and identical uniforms without insignia, as previously worn by Russian troops during Russia’s illegal and illegitimate seizure of Crimea, is a grave development,” Rasmussen said in a statement.
But Russia’s Lavrov warned that the Geneva talks would be in jeopardy if Kiev used force against “residents of the southeast driven to despair”.
Pro-Russian protesters in the region fear a loss of their rights to speak Russian and the collapse of an already depressed economy if their government cuts ties with their close and historical ally.
Many of the pro-Russian protests have only drawn crowds of a few hundred and local polls showed the majority of citizens in the Russian-speaking east preferred to remain part of Ukraine.