"This involves restrictions on the movement of Russian diplomats in our country," he said, quoted by the French news agency AFP.

The Russian embassy will soon be officially informed of the decision, Sikorski said at a press conference in Brussels, where EU foreign ministers are meeting today.

The movement restrictions in Poland will not apply to the Russian ambassador in Warsaw, according to the head of Polish diplomacy.

Quoted by the Russian news agency RIA Novosti, the Russian ambassador in Warsaw, Sergei Andreyev, said that he had not yet been officially informed of the measures taken.

When the decision comes into force, embassy staff in Warsaw will not be able to leave the administrative subdivision of Mazovia, where the Polish capital is located.

Consulate staff will only be able to travel within their respective regions, Sikorski said.

"We hope that other [countries] will follow our example," the minister said, quoted by the Spanish news agency EFE.

Sikorski said there was evidence that the Russian state was involved in preparing acts of sabotage in an EU-wide campaign.

"In Poland, one man has already been arrested for almost carrying out an act of sabotage and there are other suspects. We hope that the Russian Federation will understand this as a very serious warning signal," he said.

Sikorski also alluded to a recent increase in the number of migrants and asylum seekers arriving at the Polish-Belarusian border, which Warsaw describes as an act of "hybrid warfare" by Moscow's ally Belarus.

Estonian Foreign Minister Margus Tsahkna also warned in Brussels about "Russia's provocations".

"Russia is just trying to test our limits and play on our fears, the fear of an escalation" of the ongoing conflict with Ukraine, he told the French news agency AFP.

Two months ago, Estonia suffered "the biggest cyberattack in its history", when three billion "illegal requests" entered the government server in less than four hours, Tsahkna said.

In Estonia, 98% of administrative procedures are carried out online.

Tsahkna said that Estonia had managed to solve the problem, but insisted that the EU must react and adopt new sanctions in the face of Russia's multiple hybrid attacks.

At the end of April, and already in the countdown to the June European elections, France, Germany and Poland called for stronger measures against Russian disinformation operations in the EU.

So-called hybrid attacks often target a country's critical infrastructure through computer manipulation, but can also consist of disinformation campaigns through social networks.

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