As protesters threw eggs and set off smoke bombs, Ukraine's parliament has extended the Russian Black Sea Fleet's lease at a Crimean port for another 25 years.
Russia's parliament ratified the deal in a more sedate session.
The agreement, reached last week by the two country's presidents in a clear sign of Russia's renewed influence in Ukraine, extends the fleet's lease by 25 years after the old lease expires in 2017, The Press Association reports.
The rent Russia pays for a newly extended lease on its Black Sea base in Ukraine is high but not overpriced, the Russian President said.
"The rent we are paying for our fleet base is high but it is not excessive. It is not excessive because we have a strategic partnership [with Ukraine]," Dmitry Medvedev said.
A deal, extending the lease on a Russian base in the Ukrainian port of Sevastopol for 25 years after the current lease expires in 2017, was ratified simultaneously by the Russian and Ukrainian parliaments on Tuesday. In return for the lease, which may be further extended by five years, Ukraine will receive a 30% discount on Russian natural gas.
"We hope such relations will continue forever; they are ancestral links. Such friendship should be accompanied by mutual support," Medvedev said, adding that the agreement is beneficial both for Moscow and Kiev, RIA Novosti says.