Poland accused Belarus on Wednesday of staging an armed intrusion on its border.
Foreign Minister spokesman Lukasz Jasina said unidentified uniformed individuals armed with guns crossed into Polish territory from Belarus late Monday.
Belarusian charge d'affaires Alexander Chesnovsky was summoned to the ministry because of "a deliberate escalation" of the migrant crisis at the Polish-Belarusian border, he added.
"Deputy Foreign Minister Piotr Wawrzyk forwarded an emphatic protest against the violation of the Polish state border," the ministry said.
Urging Belarus to explain the incident, he pointed out that Poland deems such actions unacceptable and intolerable.
The EU and Poland claim the flow of migrants has been organized by Belarus as a form of hybrid warfare devised to press the EU about sanctions it imposed on Minsk, which denies the allegation.
