Ukrainian President Viktor Yanukovych is reportedly stopping off in Russia on his way home from an official trip to China.
Ukraine's UNIAN news agency reported on December 6 that Yanukovych will make a working visit to the Black Sea port of Sochi, where he is to hold talks with Russian President Vladimir Putin.
In Moscow, there was no immediate confirmation of the meeting.
Yanukovych has been on a four-day visit to China. He had been expected to return directly to Ukraine, where pro-European protesters have vowed to continue their blockade of government buildings amid police warnings of a crackdown.
Addressing protesters on December 6, opposition leader and boxing champion Vitaliy Klitschko said that "together we can win."
"We will continue to block the courts and tomorrow the prosecutor's office," he said. "We will move and do anything so that we are heard. And with every day we become more numerous. And all of Ukraine will rise, because she does not want to live by the proposals of the current government because it has shown many times that it does not want to work. And that is why we, the Ukrainian people, will show them that Ukraine is a European country. Glory to Ukraine."
Kyiv police chief Valery Mazan threatened that his forces would act if protesters defy a court order to stop blockading government buildings by December 9.
Prime Minister Mykola Azarov, meanwhile, accused some protesters of being "Nazis" and "extremists," while Deputy Prime Minister Serhiy Arbuzov rejected the opposition's demand for early elections.
Many foreign ministers of Western countries have been voicing support for the protesters during a meeting in Kyiv of the Organization for Security and Cooperation in Europe (OSCE).
The demonstrators are demanding the ouster of the Ukrainian government after Yanukovych abandoned plans to sign a trade and association deal with the European Union.
Moscow has strenuously opposed the signing, seeking instead that Ukraine join a Russia-led Eurasian Customs Union.
Yanukovych and Putin previously met for surprise talks in Moscow in early November, ahead of the Eastern Partnership summit that took place in Vilnius at the end of that month.
With reporting by Reuters and unian.info