Poland accused Belarus on Wednesday of staging an armed cross-border intrusion and said it had summoned the Belarusian charge d'affaires to protest over what it said was "a deliberate escalation" of the migrant crisis at the frontier.

Belarus rejected the allegation as unfounded and intended to sully its image.

Poland has imposed a state of emergency at the border to stem a surge in the number of migrants trying to enter its territory via Belarus.

Poland's foreign ministry said unidentified uniformed individuals armed with long guns had crossed into Polish territory from Belarus on the night of November 1.

"Deputy Foreign Minister Piotr Wawrzyk forwarded an emphatic protest ... against the violation of the Polish state border, emphasizing that the actions taken by the Belarusian authorities in recent weeks have the increasingly evident hallmarks of a deliberate escalation," the ministry said in a statement.

Belarusian State Border Guard Committee spokesperson Anton Bychkovsky denied the accusation, which he said was aimed at allowing Poland to extend its state of emergency at the border.

"This suggests that the main purpose of these actions lies in the field of the escalation of tension and further attempts to create a negative image of Belarus," the official Belta news agency quoted him as saying.

The summoning of Belarusian envoy Alexander Chesnovsky, which took place on Tuesday, was the third time in a month that he has been called in to answer questions about the situation at the border, where hundreds have been trying to cross illegally every day.

(With input from Reuters)