It said on Twitter that the illegal migrants hailed from countries including Iraq, Syria and Yemen.
Twelve Iraqi citizens were detained after they crossed to the Polish side through the Świsłocz River in the east of the country, the Border Guard tweeted.
Since the start of this year, there have been more than 2,200 attempts to cross illegally into Poland from Belarus, the border agency's data showed.
To stave off an influx of illegal migrants from Belarus, Poland has introduced new, stricter border protection rules and is building a 5.5-metre-high, 180-kilometre-long protective wall along its frontier with the Russian ally.
Last year, the European Union, NATO and the United States accused Belarus' strongman leader Alexander Lukashenko of orchestrating a migrant crisis at the Polish-Belarusian border in retaliation for Western sanctions against his regime.
Source: IAR, PAP