Andrzej Pisalnik, a journalist and activist of the Union of Poles in Belarus (ZPB), told Polish Radio on Wednesday morning that police had entered the apartment where he and his wife, Iness Todryk, reside.
According to the independent Belarusian Association of Journalists, after the search, the Pisalniks were detained and taken from Grodno to Minsk. Information regarding the detention and transport of the two activists was confirmed by PAP sources in Grodno.
Mr Pisalnik is the director of the ZPB's Znadniemna.pl web portal.
On Wednesday, the prosecutor’s office in Grodno claimed that Pisalnik had broken the law by reporting that an "anti-Polish" campaign was underway in Belarus and stated that he had been issued an "official warning."
The prosecutor's office went on to say, as quoted by the BielTA news agency: "The content of Andrzej Pisalnik's public statements is not in conformity with the requirements of Belarusian law regarding national minorities and the counteraction of extremism."
As Mr Pisalnik later explained in an interview with PAP, he was warned that he should not make statements in his commentaries, including those written for foreign media, which imply that the Polish minority was being "persecuted" by Belarusian authorities.
Polish authorities, as well as the EU and other countries, have called on Belarus to comply with international norms regarding the treatment of minorities and to release all imprisoned activists.
Seated in Grodno, a city with a large Polish population, the ZPB is the biggest Polish diaspora organisation in Belarus. In 2005, the authorities in Minsk revoked its registration. The union's statutory activities include nurturing Polish culture, teaching the language and maintaining memorial sites.