The controversial seizure was revealed on Saturday afternoon by Warsaw’s Deputy Mayor Tomasz Bratek, who announced that Warsaw city authorities had “taken possession” of the building. He was referring to a communist-era building complex in central Warsaw’s Ochota district, which, according to Moscow, belongs to the Russian government. The property was originally part of the Soviet embassy complex, but was later transformed into a high school and community center specializing in Russian language and culture. Many of its students were children of Russian diplomats who are stationed at the nearby Russian embassy. It has fallen into disuse in recent years.

Poland claims that the Russian government never officially bought or leased the property, and that it had been using it without permission for over three decades. Warsaw city officials maintain that the building belongs to the Warsaw city council and that they have repeatedly asked Russia to vacate the building, but to no avail. In recent years, the Polish government has been accusing Russia of using the high school as a cover for espionage activities, and claims that the use of the building by Moscow violates Polish sovereignty while also constituting a security threat.

Late on Saturday, the Russian government strongly denied the allegations and accused the Polish government of engaging in anti-Russian propaganda. It was later reported that Russia had called for an emergency meeting of the United Nations Security Council (which it currently chairs) to discuss the matter. The United States and other Western countries have not yet commented on the incident, but are likely to express support for Poland’s actions, given their own concerns about Russian intelligence activities in the region.

The seizure of the high school building is just the latest incident in a long list of espionage and counter-espionage incidents involving Russia and its neighbors in Europe. Since the Russian invasion of Crimea in 2014, such incidents have increased considerably. The seizure of the high school building in Warsaw highlights the continuing tensions between Russia and its neighbors in Europe, as well as the centrality of intelligence-gathering and counter-intelligence efforts in the region.