Poland will increase the number of troops at its border with Belarus after two helicopters from Belarus violated the country's airspace today, the ministry of defence said in a statement.
According to the statement, NATO has been informed of the incident.
The Belarusian defence ministry said that military helicopters have not violated the border with Poland.
"Accusations of a violation of the Polish border by Mi-24 and Mi-8 helicopters of the Belarusian Air Force and air defence forces are farfetched and made by the Polish military and political leadership to justify the build-up of forces and means at the Belarusian border," the ministry said.
Earlier today, Belarusian leader Alexander Lukashenko taunted Poland over the presence of Russian Wagner mercenaries near the NATO country's border, saying Warsaw should thank him for keeping them in check.
Belarus' charge d'affairs was called in to explain the situation.
An unspecified number of the Wagner fighters who staged a brief mutiny in Russia in June have since moved to Belarus.
They have begun training Mr Lukashenko's army, prompting Poland to start moving more than 1,000 of its own troops closer to the border.
Mr Lukashenko, a close ally of Russian President Vladimir Putin, joked at a meeting with him last month that some of the fighters were keen to press into Poland and "go on a trip to Warsaw and Rzeszow".
State news agency Belta quoted him today as saying that the Poles "should pray that we're holding onto (the Wagner fighters) and providing for them".
"Otherwise, without us, they would have seeped through and smashed up Rzeszow and Warsaw in no small way. So they shouldn't reproach me, they should say thank you."
Rzeszow is a city in southeast Poland near the Ukrainian border.
On Saturday, Polish Prime Minister Mateusz Morawiecki said a group of 100 Wagner fighters had moved closer to the Belarusian city of Grodno near the Polish border, describing the situation as "increasingly dangerous".
In his latest comments, Mr Lukashenko appeared at first to deny that, then immediately to row back on the denial.
"Suddenly, I hear recently, Poland went berserk that allegedly some detachment is coming here, as many as 100 people," he said.
"No Wagner detachments of 100 people moved here. And if they did, then only to transfer their military experience to (Belarusian) brigades concentrated in Brest and Grodno."
Mr Lukashenko has helped Mr Putin in the Ukraine war by letting him launch it in part from Belarusian territory and allowing the use of his bases to train Russian troops.
He has not committed his own troops to the war but has said they will benefit from training by Wagner, which took part in some of the fiercest battles of the conflict.
"I have to teach my military, because an army that does not fight is half an army," he said.
Meanwhile, the White house has said the US is not aware of any specific threat posed to Poland or other NATO allies by the presence of Wagner Group forces in Belarus
White House national security spokesman John Kirby told a briefing that the United States was watching the situation closely.
