Putin was scheduled to meet with the country's embattled pro-Western president Viktor Yushchenko and Prime Minister Viktor Yanukovych.
This is the Russian leader's first trip to Ukraine since the more pro-Russian Yanukovych returned to power after his party won the most votes in March parliamentary elections.
Last month, Russia announced that Kiev would see the price for gas imports increase less than its neighbors. In turn, Russian Premier Mikhail Fradkov said the Kremlin would like Kiev to "synchronize" its entry to the World Trade Organization with Moscow. Yanukovych has put on hold a drive for NATO membership that had irritated Russia.
Moscow is also pushing Ukraine to join a common economic space with Russia, Belarus and Kazakhstan, but Ukraine under Yushchenko's presidency has been reluctant to fully commit.
Russia is Ukraine's biggest trading partner, and Ukraine is heavily dependent on natural gas supplies from Russia. A dispute over gas prices earlier this year caused Moscow to temporarily cut off supplies to Ukraine, a shutdown that was also felt in Western Europe, which receives much of its Russian gas via Ukrainian pipelines. It was widely seen as punishment for Ukraine's pro-Western policies.
Since Yushchenko's election, Russia and Ukraine have also sparred over issues including the presence of Russia's Black Sea Fleet on Ukrainian territory and the use of lighthouses on its Crimean peninsula.
This week, Yushchenko expressed hope that the presidents of the two neighbors would manage to find a solution to the remaining disputes.
"I am sure that our meeting will be effective," he said. "Ukraine always was and will be a friend of Russia."
The Kremlin noted in a statement that relations between Russia and Ukraine have grown stronger this year on the basis of "principles of good neighborly relations, pragmatism and mutually advantageous cooperation."
Analysts say the visit show that relations between Russia and Ukraine are improving and becoming pragmatic and less political. But they predicted that none of the really disputed issues would be solved during this visit.
"Yushchenko does not demonstrate a desire to adjust relations with Russia. His team does its most to provoke Russia," said political analyst Mykhailo Pohrebinsky.
Yushchenko's office has said that Foreign Minister Borys Tarasyuk, considered one of Ukraine's most pro-Western politicians, will participate in the meetings. Yanukovych asked parliament to fire Tarasyuk, which it did, but a court froze the ruling and Yushchenko reappointed him.
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