The Czech Foreign Ministry said it filed a lawsuit against Russia for compensation of 53 million crowns over lease payments on land in Prague and other cities used by the country’s embassy.

In May, the Czech centre-right government rescinded orders from the 1970s and 1980s, made by the country’s then Communist rulers, that granted Russia the use of dozens of plots of lands free of charge.

Russia would henceforth have to pay leases on the plots, the foreign ministry said after the orders were cancelled in May.

That decision move marked a further deterioration of bilateral diplomatic relations that have been frosty since before Russia’s invasion of Ukraine.

Foreign Minister Jan Lipavsky said on Wednesday the lawsuit, filed in a Prague court, was for “unjust enrichment” by Russia over the past three years.

“We took this step because we did not receive any response (from Russian authorities) during pre-court calls,” he said in a statement, adding the ministry would not give further details.

Czech European Affairs Minister Martin Dvorak said in May that unauthorised profits from the land could not be allowed to support the “occupation of Ukraine”.

Russia’s Foreign Ministry said that retroactive demands for rent looked “like a ransom demand at the state level.”

The Russian embassy did not immediately respond to an emailed request for comment on Wednesday.

Czech and Russian relations have deteriorated in the past two years since Prague, in 2021, accused Russian intelligence agents of being behind explosions at an arms depot in the Czech Republic in 2014.

The Czech parliament designated the Russian government as terrorist last November for its aggression in Ukraine.