Warsaw has promised to move additional troops to the Polish border with Belarus and notified Nato that two Belarusian helicopters violated its airspace during military exercises on Tuesday.
Minsk denies the claim its machines entered Poland’s territory.
Poland initially denied any incursion had taken place but changed its mind after viewing video evidence on social media, showing what appeared to be Belarusian helicopters near the northeastern Polish village of Białowieża.
The Polish defence ministry said in a statement the violation “took place at a very low altitude, hampering detection by radar systems” and noted a growing number of “hybrid actions against Poland” in the region.
“There was a violation of Polish airspace by two Belarusian helicopters that were training near the border,” said the ministry.
In response, Poland’s defence minister Mariusz Błaszczak announced an increase in the number of Polish troops at the border with additional hardware backup, including helicopters.
The deputy defence minister Wojciech Skurkiewicz described the alleged incident as a “completely dangerous” provocation.
“If such situations occur and escalate, our reaction will be appropriate to the potential danger,” he told Poland’s PAP news agency.
Meanwhile, Poland’s foreign ministry summoned the chargé d’affaires of the Belarusian embassy to demand that Minsk “explain immediately the incident in detail”.
“The Polish side underlined that the incident is considered as another element in escalating the tension at the Polish-Belarusian border,” it added. “Poland expects Belarus to refrain from this type of activity.”
Minsk was quick to dismiss the allegations from Warsaw as “far-fetched”.
“They have been made up by the Polish military and political leadership to justify the build-up of forces and means at the Belarusian border,” added a government statement.
For three years Poland has accused Belarus of systematically luring migrants from African countries and the Middle East with the promise of passage across its border into Poland and the EU, claims Minsk denies.
At the weekend, Polish prime minister Mateusz Morawiecki warned that a group of 100 mercenaries from the Wagner group had moved closer to the Belarusian city of Grodno, near the Polish and Lithuanian borders.
Minsk has denied this, saying the Wagner mercenaries are closer to Brest, which is further south towards the Ukrainian border.
While Mr Morawiecki and his ministers warn of a plan to destabilise his country before an October general election, suggesting Wagner mercenaries may pose as asylum seekers, domestic critics accuse the ruling Law and Justice (PiS) party of exploiting fear and uncertainty in the region for political gain.
After the border incident, deputy prime minister Jaroslaw Kaczynski, chairman of PiS, said Poland will step up its programme to fortify the 400km border with Belarus. Since 2022, nearly half of the border has been fitted with a 5.5 metre-high security fence.
On Monday international analysts weighed into the debate. The Institute for the Study of War, a US think-tank, said in an analysis that “Wagner forces in Belarus pose no military threat to Poland ... until and unless they are re-equipped with mechanised equipment”.
A Pentagon spokesman said Washington was working with its Nato allies to ensure that every inch of alliance territory remains secure.
