Ukraine's new leader signed a landmark EU pact yesterday that drew immediate threats of retaliation by Russia in its standoff over the former Soviet country's future with the West.
President Petro Poroshenko hailed the Association Agreement - a 1,200-page document defining the political and trade terms under which Kiev will slip from the Kremlin's embrace - as a turning point for a country that straddles a geopolitical fault line between Europe and Russia.
Poroshenko also announced a three-day extension of the week-long ceasefire that was due to expire at 10pm local time on Friday. Insurgent leader Alexander Borodai had said earlier that the rebels were ready to extend the ceasefire if Poroshenko was and would also soon release European observers they have been holding for weeks.
The deal also bursts Russian President Vladimir Putin's dream of enlisting Kiev in a Moscow-led alliance that could rival the European Union and Nato. The Kremlin immediately vowed to take "all the necessary measures" against Ukraine.
Yet the pact is just as unpopular in Ukraine's Russified east, where a bloody separatist insurgency rages.
Ukraine's military said five more soldiers died overnight in attacks by rebels who had not honoured the terms of a temporary truce agreed by their own commanders.
The European Union also sealed identical partnership pacts with Georgia and Moldova, two former Soviet nations.
The agreements were signed just hours after the rebels released four monitors from the Organisation and Security and Cooperation in Europe whom they had abducted on May 26. Another four European observers and their Ukrainian translator are still being held captive.
Putin denies exerting control over the fighters and has yet to publicly address reports from Kiev and Washington of rocket launchers and even tanks crossing the Russian border into the conflict zone.
But Putin faces more economic sanctions if he fails to show he is backing Poroshenko's bid to end nearly two months of fighting that have claimed more than 440 lives.
EU leaders gave Russia until Monday to change its policy on Ukraine or face the prospect of tougher sanctions.
The EU argues that the free- trade deal will boost Ukraine's exports to the 28-nation bloc by €1 billion (HK$10.6 billion) a year and save the nation roughly half that amount in customs duties.
But Russia has warned that it would have no choice but to slap punishing trade restrictions on Ukraine after already nearly doubling its gas price.
Putin's hawkish economic adviser, Sergey Glazyev, told the BBC that Poroshenko had assembled "a Nazi government [that] is bombing the largest region in Ukraine".
Putin said Ukraine was split after being forced to choose between Europe and Russia.
"The anticonstitutional coup in Kiev, the attempts to impose an artificial choice between Europe and Russia have pushed society to a split, to a painful internal confrontation," he said.
Kiev and rebel commanders were to take part yesterday in a third round of indirect negotiations that could lead to an extension of the shaky truce.
Poroshenko said he would make a decision on extending the ceasefire, due to expire late yesterday, when he returned to Kiev. He has accused the rebels of adhering to the ceasefire in name only and killing more than 20 soldiers in the past week.
But the Ukrainina president pronounced himself ready to make every effort to resolve the country's worst crisis since its independence in 1991.
"I am ready to make peace with anybody," Poroshenko told CNN on Thursday. "I hate the idea of not to use the last opportunity to bring peace to the region," he added in English.
The United Nations said yesterday that about 110,000 people had fled to Russia from Ukraine since the rebellion started, while more than 54,000 had been displaced inside the country.
Melissa Fleming, spokeswoman for the UN's refugee agency, said that most had fled from the embattled eastern regions of Donetsk and Lugansk.
But she said it was not possible to say whether most or all of those fleeing to neighbouring Russia were from Ukraine's Russian-speaking population.
The rebels and Moscow have regularly cited claims that Russian speakers in Ukraine were under threat. But UN human rights probes have said there is little evidence for such fears.