Poland will send additional troops and military hardware to its eastern border after two Belarusian helicopters reportedly crossed into the NATO country's airspace Tuesday.

"There was a violation of Polish airspace by two Belarusian helicopters that were training near the border," the Polish Defense Ministry said in a statement.

Belarus dismissed the alleged violation as "far-fetched."

"Accusations of a violation of the Polish border by Mi-24 and Mi-8 helicopters of the Belarusian Air Force and Air Defense Forces are far-fetched and made by the Polish military and political leadership to justify the build-up of forces and means at the Belarusian border," the Belarusian Defense Ministry said.

Poland had inititially denied the incursion but then later said a "violation took place in the Bialowieza area at a very low altitude, hampering detection by radar systems."

Minsk had informed Warsaw it intended to conduct training exercises in the area prior to the incident.

Some Polish residents in the area had reported sighting Belarus helicopters overhead earlier in the day and posted photos and videos thereof on social media.

Poland said NATO has been informed of the incursion.

Minsk's charge d'affaires 'immediately summoned' over 'escalation'

Poland's Foreign Ministry said Belarus' charge d'affaires had been "immediately summoned" to explain the situation, and that Warsaw had "issued a firm protest."

"The Polish side emphasized that the incident is perceived as another element of the escalation of tension on the Polish-Belarusian border. Poland expects Belarus to refrain from such activities," said the ministry. 

Poland and its neighboring countries on NATO's eastern flank have expressed concern regarding a possible threat from Russia's ally Belarus, where a sizeable contingent of the Wagner mercenary group is currently stationed after having fled there on the heels of what has been billed as a short-lived coup attempt against the Kremlin in June.

On Saturday, Polish Prime Minister Mateusz Morawiecki voiced alarm, claiming that a group of 100 Wagner mercenaries had moved closer to the border, and accusing them of preparing to help migrants cross into Poland as part of a hybrid effort to destabilize the country as it prepares for elections this fall.

Poland and neighboring Lithuania, both of which are EU and NATO members, have struggled to stem the tide of largely Middle Eastern and African migrants seeking to cross their borders through Belarus. 

Minsk has been accused of systematically luring migrants to come to Belarus with the intent of releasing them into the EU, a move Belarus' strongman Alexander Lukashenko has denied.  

lo, js/wd (AFP, Reuters)