A Polish soldier died on Thursday after he was stabbed on the border with Belarus by migrants trying to cross into the European Union, the army said, while Warsaw said it would demand Belarus hand over the person responsible for his death.

The border has been a flashpoint since migrants started flocking there in 2021, after Belarus, a close Russian ally, opened travel agencies in the Middle East offering a new unofficial route into Europe – a move the European Union said was designed to create a crisis.

A soldier of the 1st Armoured Brigade, refered to only by his first name Mateusz, had been stabbed by migrants trying to cross a fence on the border in late May. The army said he died on Thursday.

“Despite the help provided in the area of ​​the criminal attack on the border with Belarus and the efforts of doctors, his life could not be saved,” it said in a statement.

In recent weeks there has been an increase in the number of migrants trying to cross illegally and border guards have reported a number of violent incidents.

“We demand that (Belarussian) authorities establish the identity of this murderer and hand him over to Polish authorities,” Foreign Minister Radoslaw Sikorski said.

A protest note would be handed to the Belarussian charge d’affaires later on Thursday, he said.

Poland has recently announced plans to beef up the border and reintroduce a 200-metre buffer zone.

Belarus rejects the accusation that it helps to channel migrants to the Polish border.