Ukraine's armed forces are on "full combat alert" against a possible Russian invasion, Kiev said yesterday, as pro-Kremlin insurgents tightened their grip on the increasingly chaotic east of the country.
Rebels stormed the regional police building and town hall in the eastern Ukrainian city of Gorlivka, local officials told AFP, adding to more than a dozen locations already under their control.
The new seizure followed clashes in nearby Lugansk late Tuesday, as hundreds of pro-Russia protesters spearheaded by a heavily armed mob attacked the police station.
Yesterday, the rebels lifted their siege of the building after the police chief promised to step down.
Ukraine's interim president Oleksandr Turchynov told his cabinet the nation's armed forces were on "full combat alert" as fears grew in Kiev that Russia could mount an armed invasion of the ex-Soviet republic.
"The threat of Russia starting a war against mainland Ukraine is real," he said.
Turchynov urged "Ukrainian patriots" to bolster the beleaguered police force, which he has criticised for "inaction and in some cases treachery". Police are "helpless" and "some of them even help and cooperate with the separatists," he charged.
The West has accused Russia of fomenting the crisis and backing the rebels and has imposed sanctions to try to get Moscow to back down.
The United States and EU members see the insurgency as a bid to destabilise Ukraine ahead of the elections but Moscow denies it has a hand in the rebellion.
President Vladimir Putin insisted to reporters late Tuesday that there were "neither Russian instructors, nor special units, nor troops" operating in Ukraine.
Opening another front in the war of words between Washington and Moscow, Putin warned the sanctions against his country could harm Western interests in Russia's lucrative energy sector.
The Russian president's comments threaten the operations of some of the world's biggest energy companies in the resource-rich country -- once viewed as a reliable alternative to unstable natural gas and oil-producing countries in the Middle East.
Russian officials have accused the United States of wanting to reinstitute "Iron Curtain"-style policies and warned the sanctions would "boomerang" back to hurt it.
But the tensions are already having an impact on the Russian economy, which the International Monetary Fund yesterday announced was already "experiencing recession".
But Washington would not let up on Moscow, as relations between them reached a low not seen since the end of the Cold War.
Vowing to "defend every single inch" of Nato territory, US Secretary of State John Kerry urged Moscow to "leave Ukraine in peace".
Although Ukraine is not a Nato member, several of its neighbours are, and the Pentagon is boosting military support for them as they express concerns over Russia's actions.
In particular, the US is planning to beef up training exercises planned for June in the Baltic states.
Meanwhile, in a small chink of light amid what EU foreign policy supremo Catherine Ashton called a "downward spiral of violence and intimidation", there were hopes a team of kidnapped international monitors from the OSCE could soon be freed.