Kiev - Ukraine's new leaders named a strongly pro-Western cabinet on Wednesday as brawls erupted between rival factions on the volatile Crimean peninsula and Russian President Vladimir Putin ordered snap military drills near the border with the ex-Soviet state.
Kiev is grappling with the dual threats of separatism and economic default as it tries to recover from three months of protests that triggered pro-Russian president Viktor Yanukovych's oustinger following a week of carnage in which nearly 100 people died.
The interim leaders tried to secure the splintered nation's confidence by naming opposition icon Yulia Tymoshenko's top ally Arseniy Yatsenyuk as prime minister in front of about 25 000 people on Kiev's Independence Square, the heart of Ukraine's worst protests since independence in 1991.
But the wave of secessionist sentiment that gripped the Russified south-eastern parts of Ukraine following the fall of the pro-Kremlin government boiled over in Crimea, as several thousands led by pro-Russian Cossacks squared off against a force spearheaded by Muslim Tatars.
Local health authorities said one man died of a heart attack during the mayhem in the port town of Simferopol, while several were injured in scuffles that involved pepper spray and saw several bottles being hurled.
Meanwhile Putin ordered his military to undergo snap readiness drills - one of several announced in recent months - across a western swathe of Russia that borders the northeast corner of Ukraine.
"The commander-in-chief has set the task of checking the capability of the armed forces to deal with crisis situations posing a threat to the military security of the country," Defence Minister Sergei Shoigu said.
He also announced Russia was taking measures to ensure the security of its Black Sea naval fleet based in Crimea - a scenic peninsula that had answered to Moscow for centuries until being handed to the Ukrainian Soviet republic as a gift in 1954.
Russia has been venting daily outrage at the meteoric turn of events in a neighbour that Putin views as vital to his dream of building a post-Soviet alliance that could rival the EU and Nato blocs.
US Secretary of State John Kerry attempted to ward off any ambitions Putin may have to use force to alter the political outcome in Kiev.
"We are making it clear that every country should respect the territorial integrity here, the sovereignty of Ukraine. Russia said it will do that, and we think it is important Russia keeps its word," Kerry stressed.
The interim government's headaches have been compounded by Moscow's decision to freeze a massive bailout package that Putin promised to Yanukovych as his reward for rejecting closer EU ties in a surprise November decision that sparked the mass protests.
Fears of a catastrophic default by Ukraine - which is seeking $35bn in Western aid to keep functioning - saw the local currency sink 4% and reach a record low against the dollar on Wednesday.
The deposed Yanukovych - who is wanted for "mass murder" - is widely believed to have gone into hiding in Crimea with his two sons and a small team of heavily-armed guards.
The new interim prosecutor general insisted that Yanukovych was still in Ukraine while also requesting an international arrest warrant for both the fugitive ex-leader and the ousted interior minister Vitaliy Zakharchenko - a hate figure among protesters for ordering the deadly use of force.
There was further confusion when Putin's spokesperson was forced to say he had no information about a private Russian TV report claiming that Yanukovych was hiding out in a government health resort near Moscow called Barvikha.
The RBK channel cited an unnamed "major Russian businessman" as its source and said the information had been confirmed by a "high-ranking Russian official".
Top among interim president Oleksandr Turchynov's concerns are fears of mob violence in Crimea. Crowds have already ousted the mayor of Sevastopol - home to the Kremlin's navies for the past 250 years - and appointed a Russian citizen in his place.
However Kiev's new rulers were offered some short-term relief when the Crimean parliament speaker cancelled a planned vote on the peninsula's secession.
But Wednesday's scuffles threatened to continue across the peninsula and spread to other pro-Russian regions such as Yanukovych's native industrial base of Donetsk.
Three of Ukraine's post-Soviet leaders issued a joint statement accusing Russia of "resorting to direct intervention in the political life of Crimea".
Russia must "show respect to the choices made by the Ukrainian people and the Ukrainian government", said a statement posted by former president Viktor Yushchenko and also featuring the names of ex- Moscow ally Leonid Kuchma and former leader Leonid Kravchuk.
New pro-Western team
The new cabinet is expected to win easy and quick confirmation by parliament after mass defection from Yanukovych's ruling Regions Party put the chamber firmly in the opposition's hands.
Several nominations were a clear sign that the protesters were taking charge of Ukraine.
Journalist Tetyana Chornovil - attacked in December after filing reports about Yanukovych's purported wealth - was nominated as head of a new anti-corruption committee.
And prominent opposition leader Dmytro Bulatov - who emerged with a part of his ear missing and caked in blood after being kidnapped and tortured by what he believes were pro-Yanukovych thugs in January - was asked to be Ukraine's ministry of sport and youth.
The vital economy ministry was offered to Kiev School of Economics President Pavlo Sheremeto.
New acting interior minister Arsen Avakov also disbanded the elite Berkut riot police force that many Ukrainians have feared since it was first formed in the dying years of Soviet rule.