PRAGUE — Forty years to the day after the Soviet Army crushed a stirring for greater freedoms here known as the Prague Spring, it was not a column of tanks that government officials said they feared most, but an assertive Russia shutting off the spigots of its crucial supplies of oil and gas.

The sight of Russian forces occupying swaths of Georgian territory dredged up bad memories across the former Warsaw Pact. Here in the Czech Republic and in neighboring Slovakia, the clashes in the Caucasus coincided with preparations for the commemoration on Thursday of the anniversary of the day when Czechoslovakia’s experiment with a more open form of Communism was halted violently on orders from Moscow.

On a sunny afternoon, children posed for photos with men dressed as Russian soldiers on a tank in front of the National Museum on Wenceslas Square. The carnival atmosphere contrasted starkly with the historical images of modern tanks pushing through the delicate old streets of Prague and of the glum, disbelieving looks on the faces of the Czechs.

At the events to commemorate that solemn occasion here, there was no shortage of people expressing fears that an emboldened Russia would embark on military adventures beyond Georgia. The unease generated by Russia’s recent military success was palpable among those who had lived through the occupation of their country.

“The Russians were backed up in their barracks,” said Hana Mrazova, 60, a retired resident of Prague who said she had vivid memories of the invading troops pouring into her city. “Now they’re everywhere again.”

The Russian military has not come close to achieving such ubiquity, but many Czechs often feel as though the country’s giant energy concerns have. That is why it is the threat of economic pressure more than military coercion that most concerns officials here.

“Everybody in this region saw joining NATO and the European Union as the tools to get all the security you needed. It was seen as a panacea,” said Vaclav Bartuska, the Czech Republic’s ambassador at large for energy security. “It doesn’t solve all your problems.”

That was seen in July when Russian oil deliveries fell suddenly and sharply after the Czech government signed a deal to host a tracking-radar station for an American antiballistic missile system that Moscow opposed.

Russian officials said it was a commercial issue and denied that there were any political undertones. Analysts here are skeptical of the explanation. “You can manage this kind of issue by cutting a little supply in all directions,” said Jiri Schneider, program director at the Prague Security Studies Institute, an independent research group here.

“We’re not concerned about Russian tanks nowadays,” he continued. “We’re not even concerned about missiles being targeted. We are concerned about the mentality which is tolerated or the notion that we should understand, that this is somehow a natural reaction to the Russian humiliation after the end of the cold war.”

Mr. Bartuska praised his predecessors for anticipating the problem and diversifying their oil supply routes. The Czech government in the 1990s built an alternative pipeline to Germany, thereby lessening the country’s reliance on Russia.

That alternative supply route has allowed them to cover the continuing oil shortfalls from Russia. Yet like many of its neighbors, the Czech Republic still relies on Russia for the majority of its natural gas, which is even harder to replace in the event of supply disruptions than is oil.

The announcement in 2005 of a planned gas pipeline under the Baltic Sea between Russia and Germany, bypassing countries like Poland and Lithuania, stirred fears in the region by raising the possibility of Russia’s pressing its former Warsaw Pact states with gas cutoffs while not disturbing richer clients to the west.

Then, like much of the world, the Czechs watched with great concern as Moscow cut off gas supplies to Ukraine at the beginning of 2006. Those concerns were amplified later that year when, blaming technical problems, a Russian pipeline operator cut off supplies to a refinery in Lithuania after it was sold to a Polish company.

“In Georgia, just weapons were used, military action,” said Pawel Zalewski, who was chairman of the foreign affairs committee in the Polish Parliament from 2005 to 2007. “In Central and Eastern Europe, they will use energy as a tool, gas and oil, mainly gas.”

It is a form of influence that Russia appears far more comfortable exercising against the former Soviet states and Warsaw Pact allies than against the established European powers.

“The Western European countries are in, I think from their point of view, another grouping,” said Angela Stent, director of the Center for Eurasian, Russian and East European Studies at Georgetown University.

At a time when many Czechs, especially those too young to remember the upheaval of 1968, seemed more interested in the up-to-the-minute results from the Olympics, the images of Russian tanks on Georgian territory gave added resonance to historical events here that are now decades in the past and an anniversary that, in recent years, was receding in relevance to day-to-day life in the country.

But it was the a group of people draped in Georgian flags on Thursday in Wenceslas Square who served as the stark reminders of the present. “As soon as I arrived here, Czech people are clapping here and saying, ‘Stop Russia, support Georgia,’ ” said Zurab Laliashvili, 26, a Georgian living in Prague while he worked on a doctorate in economics.

There has been disagreement within the Czech government over whether it was fair to compare the Czechoslovak historical experience the events in Georgia, but among witnesses to the events of 1968, no such disagreement was evident.

“Forty years ago I was standing right here, and I know exactly how he feels,” said George Volak, 63, a retiree. “Anyone who thinks the Russians will leave Georgia is wrong.”

Copyright 2008 The New York Times Company