Maszkiewicz's father is on a hunger strike until he says his son is released.
In Minsk, the Belarusian Foreign Ministry says it has received no official notice of the demand to free Maszkiewicz.
Relations between the two countries have been strained for months, and Poland openly backed the main opposition candidate to Lukashenka.
THE AUTHORITIES GET TOUGH: RFE/RL's Belarus Service filed these images from the police action against the March 25 demonstration in Minsk. Photographs by Maks Kapran.
THE COMPLETE PICTURE: Click on the image to view a dedicated page with news, analysis, and background information about the Belarusian presidential ballot.