Ukraine's ousted pro-Moscow president emerged defiant Thursday from five days in hiding as the country's new leaders issued a blunt warning to Russia against any aggression on the volatile Crimean peninsula.

Anxious Western governments voiced fears about the "dangerous" situation in Crimea after dozens of pro-Kremlin gunmen in combat fatigues seized government buildings in the autonomous republic and pleaded with Moscow not to escalate tensions.

News agencies in Moscow said fugitive president Viktor Yanukovych would hold a press conference in Russia on Friday in his first public appearance since fleeing Ukraine at the weekend.

Russian President Vladimir Putin had stoked concerns Wednesday that Moscow might use its military might to sway the outcome of Ukraine's three-month standoff by ordering snap combat readiness drills near the border with the ex-Soviet state.

Interim president Oleksandr Turchynov responded by telling parliament any movement of Russian troops out of their Black Sea bases in Crimea "will be considered as military aggression".

Ukraine's bloodiest crisis since its 1991 independence erupted in November when Yanukovych made the shock decision to ditch an EU trade pact in favour of closer ties with old master Russia.

Yanukovych -- deposed after a week of carnage in Kiev claimed nearly 100 lives -- broke his silence by telling Russian news agencies he still viewed himself as president.

Ukraine has appeared to take a decisive swing back toward the West by ousting Yanukovych and replacing his team with a new brand of younger politicians who will steer the nation -- torn between a Russified east and pro-European west -- until May 25 presidential polls.

The parliament overwhelmingly confirmed opposition icon Yulia Tymoshenko's top ally Arseniy Yatsenyuk as prime minister and approved the makeup of his untested but strongly pro-Western government.

"Ukraine is being torn apart," a sombre Yatsenyuk said. "But Ukraine sees its future in Europe. We will be a part of the European Union."


Russian flags over Crimea


The Russian tricolour was flying over the Crimean parliament and government buildings in the regional capital Simferopol as supporters of Moscow rule flocked in from across the scenic peninsula by car and bus.

The autonomous region's prime minister Anatoliy Mohilyov told AFP up to 50 armed men had seized the buildings and were preventing government workers from going inside.

But his predecessor Sergiy Kunitsyn told lawmakers in Kiev his local contacts said the raid involved "about 120 well-trained gunmen armed with sniper rifles... and carrying enough ammunition to last them a month."

The gunmen opened the doors to allow in lawmakers who quickly approved the staging of a regional referendum -- also on May 25 -- that would grant Crimea "national sovereignty within Ukraine on the basis of existing treaties and agreements".

Lawmakers agreed to disband the region's government and hand its powers to the heavily pro-Russian parliament.

They also appointed Crimea's Russian Unity party member Sergiy Aksyonov as "prime minister" in place of Mohilyov.

The international response to the standoff was swift and overwhelmingly critical of Russia.

US Defence Secretary Chuck Hagel said Moscow must be transparent about military exercises that are believed to involve some 150,000 troops.

"I urge them not to take steps that could be misinterpreted or lead to miscalculation," he said in comments echoed by NATO head Anders Fogh Rasmussen.

Polish Foreign Minister Radoslaw Sikorski -- a strong proponent of Ukraine's eventual EU membership -- warned of "a very dangerous game" in Crimea, while the Organization for Security and Cooperation in Europe expressed "serious concern" said it was sending envoys.

But Moscow responded by saying it was "strictly adhering" to existing treaties with Ukraine on the Black Sea fleet.

US Secretary of State John Kerry said his Russian counterpart Sergei Lavrov had told him Moscow was not behind the storming of the Crimean government buildings and "will respect the territorial integrity of Ukraine".


Yanukovych to speak in Russia


Yanukovych -- wanted for "mass murder" over the deadly protests -- had been widely believed to have gone into hiding in Crimea with his two sons.

But Russian television reported late Wednesday the 63-year-old was hiding in a government health resort near Moscow.

Yanukovych's statement Thursday did not disclose his whereabouts but said he was "compelled to ask the Russian Federation to ensure (his) personal security."

Moscow's three main agencies quoted a source in Yanukovych's entourage as saying he would give a press conference in the southwestern city of Rostov-on-Don on Friday at 1300 GMT.

Switzerland said Thursday it was prepared to freeze any funds he might have in Swiss banks.

It is unclear whether Yanukovych himself has funds in Switzerland, but his 40-year-old son Olexander opened a branch of his Management Assets Company (MAKO) in Geneva in late 2011.

He has amassed a personal fortune of around half a billion dollars (some 365 million euros) in the past three years, according to the Swiss weekly L'Hebdo.

His conglomerate reportedly controls nearly half of that country's coal production, and around a third of its electricity production and distribution.

Ukraine's new leaders meanwhile are suffering from Moscow's decision to freeze a $15-billion bailout package Putin promised to Yanukovych.

Kiev has requested as much as $35 billion in Western help and owes $13 billion in state debt payments this year -- a massive sum in a country where state reserves have shrunk to less than $18 billion.

The local currency plunged almost 10 percent to a record low against the dollar Thursday on concerns over a catastrophic default.

The leadership in Kiev won some reprieve when Kerry promised quick delivery of $1 billion in loan guarantees.

Kerry said the EU was looking at loan guarantees worth some $1.5 billion for the nation of 46 million people.

Any aid would probably be funnelled through a mechanism overseen by the International Monetary Fund which had frozen its assistance programme because of Yanukovych's refusal to make painful structural changes.

IMF chief Christine Lagarde promised Thursday to send a fact-finding mission to Kiev in the coming days to launch a "preliminary dialogue with the authorities".

German Foreign Minister Frank-Walter Steinmeier said ahead of a meeting with Lagarde on Friday the EU would likely follow Washington's example by pledging "around the same amount".