In a statement, the Polish Army Operational Command said the brief incursion had happened at 11:08 (09:08 GMT), and the helicopter had been tracked by radar.

Poland’s air defence units were operating around the clock ready to “ensure the safety of Polish airspace”, it added.

A number of Russian drones and one unarmed Russian missile have landed in Poland since the start of Russia’s invasion of Ukraine, which is not a member of Nato.

Last week, Polish Prime Minister Donald Tusk suggested Russia was planning drone and missile strikes against Poland and other countries on Nato’s eastern flank.

“In recent weeks, the Russian hybrid threat against Europeans… has intensified,” he said.

“The intent is to intimidate us and break our effort to support Ukraine. The result will be the exact opposite. We are not intimidated because we know that our security today and tomorrow is at stake in Ukraine.”

French President Emmanuel Macron said shortly afterwards that his country had been targeted by Russian hybrid attacks in the past few weeks, vowing that this would not be left “without a response”.

Macron said he had already ordered a plan to protect the country’s critical infrastructure and defence industry sites.

Hybrid warfare or hybrid attacks are loose terms which tend to describe non-military methods, for example cyberattacks, sabotage or misinformation, designed to exert pressure and destabilise an adversary.

These are quite often employed using proxies, but Russia always denies involvement in such attacks despite growing evidence to the contrary.