Medvedev and Yanukovych will meet in the Ukrainian leader’s industrial power base of Donetsk as the Kremlin is dangling the offer of cheaper gas in exchange for Ukraine’s promise of tighter cooperation with Russia.

Kiev, which has made no secret of its European Union integration aspirations, has until now steadfastly resisted Russia’s pressure.

But the seven-year jail term Ukraine handed former prime minister Yulia Tymoshenko last week triggered a dramatic deterioration in ties with the EU that could make Ukraine more vulnerable to the Kremlin’s advances, analysts say.

“The European Union does not want to let Russia take advantage of a cool-down in its ties with Ukraine,” Fyodor Lukyanov, editor of Russia in Global Affairs magazine, told AFP.

“Russia understands this and will play its own game. But it is unclear what leeway for compromise there is.”

On Thursday, Yanukovych had been scheduled to travel to Brussels for talks with EU president Herman Van Rompuy and European Commission president Jose Manuel Barroso but following the jailing of Yanukovych’s rival and opposition leader Tymoshenko, that plan is now in limbo.

The EU warned the verdict risked having “profound implications”, only to see Ukraine launch a new probe against the Orange Revolution leader over suspected embezzlement.

Ukraine is hoping to sign off on an association agreement with the European Union at a December summit in Kiev, a first step towards membership.

A European diplomat, speaking to AFP on condition of anonymity, suggested that plans for both Yanukovych’s Brussels visit and the summit could be revisited, however.

“Everything is possible, no option or development is excluded,” he said. Medvedev will try to benefit from Ukraine’s diplomatic crisis as Russia seeks to strong-arm Ukraine into joining a customs union with the ex-Soviet nations of Belarus and Kazakhstan, analysts say.

Gazprom chief executive Alexei Miller will accompany Medvedev to Donetsk, even though the summit’s official agenda is cross-border cooperation.

A Ukrainian source said last week that Miller and Ukrainian Energy Minister Yury Boiko might meet in Donetsk again on Thursday when the city will host a football match between Ukraine’s Shakhtar Donetsk and Russian club Zenit St Petersburg.

A Gazprom official could not confirm that plan Monday.

Russia has repeatedly said it could agree to sell Kiev gas at lower prices if Ukraine cedes control of its prized Soviet-era pipeline grid. Ukraine has repeatedly spurned the pressure.

Ukraine sentenced Tymoshenko for signing a gas contract with Russia in 2009, claiming it is forced to overpay by up to $8 billion.

The current tug-of-war is a stunning reversal of fortune for Russia’s ties with its neighbour.

Medvedev and Yanukovych stunned the West in April 2010 by announcing a deal to extend the lease of a Russian naval base in Crimea by 25 years in exchange for Kiev receiving a huge discount on gas imports.

Analysts say over the past months Kiev has grown disillusioned with the prospects of closer ties with Moscow, which has sought to pressure Ukraine into joining the Russian-led customs union and threatened it with sanctions.

“Viktor Yanukovych’s policies caused disappointment in Russia,” said Sergei Zhiltsov, an analyst at the Institute of Contemporary International Studies, a Moscow-based think tank affiliated with the foreign ministry.

Writing in broadsheet Nezavisimaya Gazeta, Zhiltsov said the economic incentives offered by Russia proved ineffective in its bid to bring Ukraine in its fold.

“The announcement of the Tymoshenko verdict could lead to a temporary cool-down in ties between Brussels and Kiev, but the Europeans are unlikely to abandon their earlier approach towards Ukraine,” he added.