Pro-Moscow rebels fighting in east Ukraine have vowed to press on with a disputed independence referendum, ignoring a call from Russian President Vladimir Putin to postpone the vote in a bid to ease tensions.
"The vote will happen on May 11," the leader of the self-proclaimed People's Republic of Donetsk, Denis Pushilin, told reporters.
The move reignited the crisis in Ukraine after Putin on Wednesday made a surprise call to the rebels to postpone their referendums and backed a previously disparaged presidential election planned by Kiev's interim leaders for May 25.
On Thursday, Cold War-style tensions surged again to the fore, with Russia test-firing ballistic missiles while its defence minister stressed the country's nuclear capable forces remained on "constant combat alert".
Putin had set as a condition for pushing back the referendums that the military operations waged against the rebels by the pro-Western government in Kiev must end.
After initially being caught off guard by Putin's appeal, the rebels on Thursday rejected the Russian leader's proposition after holding consultations.
"The date of the referendum will not be postponed," Pushilin said.
There were also plans to hold a referendum in Slavyansk where a Ukrainian military operation to besiege the flashpoint town was continuing, and in the eastern region around the city of Lugansk.
One Slavyansk resident who gave his name as Sergiy told AFP the referendum "must go ahead as soon as possible before the presidential election".
"Whatever happens, I'll go and vote. It seems the majority of the population is in favour of federalisation."
And Kiev vowed to press ahead with what it calls an "anti-terrorist" operation against insurgents holding a dozen or so towns and cities in the east.
"The counter-terrorist operation will go on regardless of any decisions by any subversive or terrorist groups in the Donetsk region," Andriy Parubiy, secretary of Ukraine's national security and defence council, told reporters in Kiev.
Prime Minister Arseniy Yatsenyuk said in a speech marking the Soviet victory against Nazi Germany that Ukraine was facing "a real albeit undeclared war".
Putin had also said Wednesday after his meeting with Swiss President Didier Burkhalter that Russia had withdrawn its estimated 40,000 troops from the Ukrainian border.
But NATO Secretary-General Anders Fogh Rasmussen told reporters in Warsaw he had yet to see "any indications" that Russia had actually done so.
Putin's proposals had appeared to offer the first glimmer of hope that the seemingly inexorable decline into war might be averted.
They sparked mixed reactions from a sceptical West.
German Foreign Minister Frank-Walter Steinmeier welcomed the "constructive tone" of Putin's comments, but Yatsenyuk said the Kremlin strongman was "talking through his hat".
The Ukrainian foreign ministry issued a statement saying Putin's call to push back the referendums was "just a mockery and by no means a sign of goodwill" because the plebiscites were illegal to begin with.
While the government wants to have a "full-scale national dialogue ... a dialogue with terrorists is impermissible and inconceivable," the ministry said.
Putin's spokesman followed the surprise statement by fleshing out measures to ease tensions, urging Kiev to stop its military operations to flush out rebels controlling more than a dozen towns and cities in eastern Ukraine.
Officials have said 14 troops have been killed, 66 wounded and three helicopter gunships lost in the operation against the rebels, who are estimated to have lost more than 30 fighters.
The majority of the fighting has taken place around the town of Slavyansk, where explosions and small-arms fire could still be heard overnight.
Clashes that resulted in a horrific inferno in the southern port city of Odessa last week claimed another 42 lives, most of them pro-Russian activists, pushing the death toll over the past week to nearly 90.
The violence has prompted many Western politicians to warn that the country of 46 million people was slipping towards a civil war that would imperil peace in Europe.
