The Czech Foreign Ministry summoned Russia's ambassador on Tuesday to express concerns about the use of Russian diplomatic properties.
The Czech Republic expelled around 100 Russian embassy last year in a diplomatic row over Prague's accusations of Russian involvement in a 2014 explosion at an arms depot, and the government has been one of the toughest against Moscow over its invasion of Ukraine.
"Diplomatic missions on the territory of a foreign state must respect not only the Vienna Convention on Diplomatic Relations, but also the rules and laws of the host country," Foreign Minister Jan Lipavsky said in a statement.
"Russia does not do this and does not respect the rule of law," the ministry's statement added, without providing further details.
Russia's Embassy in Prague declined to immediately respond to a request for comment.
CTK news agency reported that a newly created working group to deal with properties owned by Russia had found dozens of properties that raised doubts whether they were still used for diplomatic activities. It gave no further details.
Earlier this year, the district of Prague where the Russian embassy is located requested that a Russian school building -- unused since the Czechs expelled the Russian diplomats last year -- be made available for Ukrainian refugee children.
It was not clear if this building was among those that had raised concerns.
(Reporting by Jason Hovet; Editing by Alison Williams)