"We will take retaliatory measures so that Polish leaders, gripped by Russophobia, will deeply regret the upcoming anti-Russian measures," Russian Foreign Ministry spokeswoman Maria Zakharova was quoted as saying by the French news agency AFP.

Polish Foreign Minister Radoslaw Sikorski announced in Brussels on Tuesday that Poland will impose travel restrictions within the country on Russian diplomats, with the exception of the Russian ambassador.

Sikorski justified the move by citing the "involvement of the Russian state in a hybrid war against the European Union (EU), including Poland."

Zakharova said that Moscow does not yet know the details of the decision made by Warsaw.

"A note from the Polish Foreign Ministry with details of the decision taken has been announced. When we receive it, we will study it and take retaliatory measures," the diplomat told the Russian news agency TASS.

Once the decision comes into effect, employees of the Russian embassy in Warsaw will not be able to leave the administrative subdivision of Mazovia, where the Polish capital is located.

Consulate employees will only be able to travel within their respective regions, Sikorski said in Brussels, where a meeting of EU foreign ministers was taking place.

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

"In Poland, one man has already been detained for almost carrying out an act of sabotage and there are other suspects. We expect the Russian Federation to 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.

In late April, France, Germany and Poland called for stronger measures against Russian disinformation operations in the EU.

Read Also: Hybrid attacks. Poland restricts movement of Russian diplomats (Portuguese version)