TALLINN, Estonia – Vladimir Putin's efforts to regain influence in Ukraine after the leader he campaigned for was overthrown will be quiet and less extreme than anything like military action, analysts from Moscow to London said.

Putin, who has yet to comment publicly on the bloody ouster of Viktor Yanukovych last week, won't risk inciting a backlash against Russia as he did in 2004 by interfering directly as Ukraine scrambles to form a government and elect a president, said Olga Kryshtanovskaya, a sociologist who studies Putin at the Russian Academy of Sciences in Moscow.

"I'm confident he won't resort to direct interference," Kryshtanovskaya said. "He may use some less explicit methods of economic or other kinds of pressure, though."

Putin interrupted a state visit to Brazil in 2004 to congratulate Yanukovych on winning the presidency — before all the votes were counted. Fraud in that election sparked the Orange Revolution that kept Yanukovych out of power.

Calls for intervention

In Crimea, part of Russia until 1954 and still home to its Black Sea Fleet, there are calls for Putin to intervene, while some in the eastern industrial heartland want more autonomy. Moldova, on Ukraine's southwest border, has a pro-Russian secessionist region, and fellow former Soviet republic Georgia fought a five-day war with Russia in 2008 in a failed bid to control two Russian-backed regions.

"I don't think they'd try to do what they did in Georgia because they'd be too anxious, as everybody must be, that they'd cause the disintegration of the country, that they'll cause civil war," said Margot Light, professor emeritus at the London School of Economics.

"Russia's main task now is to maintain as many pressure levers as possible over Ukraine's future government," Jonathan Eyal, international director at the Royal United Services Institute in London, said in a research note. One of those levers may be demanding repayment of $2.3 billion of debt for oil and gas deliveries.

Ways to express dismay

"The Russians can also express their displeasure by canceling visas of Ukrainian migrant laborers working in Russia, or by imposing strict controls on cross-border trade," Eyal said. "Both were tried before, and both cause real economic pain."

Putin's also waiting to see what happens during the May 25 presidential election, which may still be won by a candidate representing the Russian-leaning east, said Arkady Moshes, head of the Russia research at the Finnish Institute of International Affairs.

"The outcome of the early elections is not predetermined," Moshes said. "The east of the country … is now quite frightened with what has happened. If a representative of the east wins a fair and free election, destabilization is still quite possible. A lot of effort by the Ukrainian liberals and by the international community will be required to keep the country stable."