Poland has seized a high school building near the Russian Embassy in Warsaw meant for the children of diplomats, igniting a harsh reaction from Moscow.

Polish police broke the doors of the school of the Russian Embassy in Warsaw earlier on Saturday, blocked the exits, and gave people who were in the building until 1700GMT (7pm local time) to leave the premises.

In a statement on its website, the Russian Foreign Ministry said Poland's "hostile actions" are a "blatant violation" of the Vienna Convention on Diplomatic Relations of 1961 and another encroachment on Russian diplomatic property.

"Such an impudent step by Warsaw, which goes beyond the framework of civilized interstate communication, will not remain without our harsh reaction and consequences for the Polish authorities and Poland's interests in Russia," the ministry stressed.

In a separate statement on Telegram, Foreign Ministry spokeswoman Maria Zakharova qualified the actions of the Polish authorities as "provocation."

"Official Warsaw has been violating the law for many years: international legislation, bilateral agreements, domestic legislation. Behaves defiantly and unlawfully. What can be described in one word — provocation," Zakharova said.

Disparity in diplomatic buildings

Since Moscow started what it calls a "special military operation" in Ukraine, neighbouring Poland, one of the main Kiev supporters, began a crackdown on Russian diplomatic missions and commercial companies.

The spat over the 1970s multi-storey building, nicknamed the "spy nest" by Warsaw citizens, has been going on for a year.

"This building belongs to the Warsaw City Hall," Polish foreign ministry spokesman Lukasz Jasina told AFP news agency, adding that the move followed a bailiff's order. The spokesman for the municipality was unavailable for comment.

Poland says there is a huge disparity in the number of diplomatic buildings each had in the other country.

"This is an illegal act. An intrusion on a diplomatic facility," Moscow's envoy, Sergei Andreyev, responded in an interview with RIA Novosti news agency, adding that Russia considers the school as "part of our diplomatic mission".

"We consider the school by the embassy to be part of our diplomatic mission," he said, saying teachers and staff lived on the territory of the building.

Andreyev said the school will continue to work in a different part of the Russian embassy's premises. "Our priority is ensuring the safety and the interests of our employees and their families."