KIEV - EU foreign ministers prepared to meet over the Crimea crisis in Athens Friday after Ukraine's Western-backed leaders blamed Russian agents and the country's ousted president for organising the bloodshed during February protests that claimed nearly 90 lives.
The explosive allegations were levelled only moments before Russia responded to the new course taken by the ex-Soviet neighbour by hiking the price it must pay for gas shipments to what Ukrainian officials say is the highest rate for any European state.
Washington reacted by warning Russia that "a country should not use supply and pricing terms as tools of coercion to interfere in Ukraine or elsewhere," said White House spokesman Jay Carney.
Moscow also lashed out at its old Cold War nemesis NATO for building up the defences of ex-Communist and former Soviet republics that have felt threatened by Russia's recent annexation of Crimea and massive buildup of forces near Ukraine.
The fierce East-West fight for Ukraine's future has exposed the deep divide that splits the nation of 46 million between those who see themselves either as culturally tied to Russia or as part of a broader Europe.
Those tensions exploded on February 18 when gunshots in the heart of snow-swept Kiev heralded the onset of pitched battles between riot police and protesters - some armed with nothing more than metal shields - that left scores dead.
Both sides have blamed the other for starting the violence, but there had been no formal probe results unveiled until acting interior minister Arsen Avakov presented his initial findings to reporters on Thursday.
Avakov's conclusion was decisive and potentially devastating for the new leaders' relations with Russian President Vladimir Putin.
He said that deposed president Viktor Yanukovych had issued the "criminal order" to fire at the protesters while agents from Russia's Federal Security Service (FSB) helped him plan and carry out the assault.
"FSB agents took part in both the planning and execution of the so-called anti-terrorist operation," Ukrainian Security Service head Valentyn Nalyvaichenko told the same press briefing.
An FSB spokesman told Russia's state-run RIA Novosti news agency that Ukraine's allegations were patently false. Russian Foreign Minister Sergei Lavrov for his part said "huge amounts of evidence" contradicted Kiev's claims.
Yanukovych fled to Russia only days after the carnage and is now wanted in Kiev for allegedly ordering police to open fire against the crowds - a charge he denies but that is likely to keep him out of Ukraine for years to come.
"Former president Yanukovych will be prosecuted," Ukrainian Prime Minister Arseniy Yatsenyuk told the BBC. "He is accused of mass murder and we will bring him to justice." Meeting under Greece's six-month EU presidency in Athens, European Union foreign ministers will discuss the Crimea and Ukraine crisis from 0930 GMT on Friday.