Ukraine's new leaders named a strongly pro-Western cabinet 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 ouster following a week of carnage in which nearly 100 people died.
The interim leaders tried to secure the splintered nation's confidence by announcing the nomination of opposition icon Yulia Tymoshenko's top ally Arseniy Yatsenyuk as prime minister before a receptive crowd of about 25,000 on Kiev's iconic Independence Square -- the crucible of Ukraine's biggest and most deadly protests since independence in 1991.
But the wave of secessionist sentiment that gripped the Russified southeastern parts of Ukraine following the fall of the pro-Kremlin regime boiled over in Crimea as an angry crowd of a few thousand led by pro-Russian Cossacks squared off against a force of a similar size spearheaded by Muslim Tatars.
Local health authorities said one man died of a heart attack during the mayhem in the port town of Simferopol. Ambulances were also called in to treat several people who suffered head contusions during scuffles that involved pepper spray and saw several bottles being hurled.
Tensions were ratched up still further when Putin ordered the 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 $35 billion in Western aid to keep functioning -- saw the local currency sink four percent and reach a record low against the dollar Wednesday.
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.
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.
Ukraine interim prosecutor general insisted that the fugitive ex-leader was still in the country while at the same time requesting an international arrest warrant for both him and ousted interior minister Vitaliy Zakharchenko -- a hate figure among protesters for ordering the deadly use of force.
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 -- who included former Moscow ally Leonid Kuchma -- 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 Kuchma and former leader Leonid Kravchuk.
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 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.
The Berkut units carried metal shields and Kalashnikov rifles as they cracked down on protesters in Kiev and brutally beat those detained -- forcing one man to strip naked in the freezing cold and parade in front of a police camera in an incident that gained infamy through the Internet.