In addition to any economic assistance the EU might offer, the U.S. has also promised help. Budgets are tight on both sides of the Atlantic, and international creditors may be wary of Yanukovych's opponents, whose previous spell in government was no economic success, but a desire to avoid instability and back what looks to Western voters like a democratic movement menaced by Russian diktat may loosen purse strings, at least to tide Ukraine over until elections.
In Russia, where Putin had wanted Ukraine as a key part in a union of ex-Soviet states, the finance minister said the next tranche of a $15-billion loan package agreed in December would not be paid, at least before a new government is formed.
Russian Foreign Minister Sergei Lavrov, according to his office, told U.S. Secretary of State John Kerry the opposition had "seized power" by force by ignoring an EU-brokered truce that would have left Yanukovych in office for the time being.
(Read more: Russia's Lavrov: Ukraine opposition doesn't deliver on deal)
But even lawmakers from Yanukovych's own party voted for his removal on Saturday and blamed him and his entourage for the crisis. Business "oligarchs" also distanced themselves from a man long seen as their representative in the presidency.
In a mark of passions dividing Ukrainians along a historic faultline between Russian and Ukrainian cultures, local television in Kerch, in eastern Crimea, showed a crowd hauling down the blue-and-yellow Ukrainian flag in front of the town hall and hoisting the white, blue and red Russian tricolour.
In a hectic round of voting in parliament, lawmakers rushed in some crowd-pleasing measures against the old administration, conscious that those still occupying Independence Square—or the Maidan—remain deeply suspicious of the political class.
They stripped Yanukovych of his abandoned country home near Kiev, complete with ostrich farm and hot tubs, its brash opulence fuelling demands that he be held to account for stealing taxpayer billions.
Turchinov said a government should be in place by Tuesday.
His ally, Tymoshenko, defeated by Yanukovych in a 2010 presidential election and later jailed for corruption, ruled herself out as interim premier. Freed from a prison hospital on Saturday after more than two years in jail, she may want time to recover and build support before running for the presidency.
As prime minister following the largely peaceful Orange Revolution of 2004-05, which overturned a first presidential victory by Yanukovych, Tymoshenko disappointed many in Ukraine who had hoped for an end to the corruption and failed economic policies that marked the aftermath of Soviet communism.
"In these days the most important thing is to form a functioning government," said Vitaly Klitschko, a former world boxing champion and also a possible presidential contender.
On Independence Square, men were still wandering around with clubs and wearing home-made body armour, helmets and in some cases ski masks and camouflage fatigues.
"We'll stay here to the very end," said one, Bohdan Zakharchenko, 23, from Cherkasy, south of Kiev. "We will be here till there's a new president."
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