WARSAW — Poland's Foreign Ministry apologized Friday after prosecutors gave Belarussian investigators financial information about a human rights activist who was then detained.
The incident comes as an embarrassment for Warsaw, which has made it a key foreign policy priority to support the pro-democracy movement in Belarus, which is located on its eastern border.
The ministry said Belarus had "taken advantage" of international procedures when it requested banking information about Ales Belyatsky — one of Belarus' leading rights activists. Polish prosecutors transferred the data to Belarus in June.
The ministry said Belarus found a way "to use the system of international procedures and agreements on financial transfers — meant to control the contemporary terrorist and criminal threats — in order to use them for repressive action against the country's own citizens."
Foreign Minister Radek Sikorski also apologized on Twitter on Friday and vowed to improve efforts to support democracy.
"I apologize in the name of the Polish republic. A reprehensible mistake despite warnings from the Foreign Ministry. We will redouble efforts for democracy in Belarus," he wrote.
Polish efforts to help Belarussians have included opening up Polish universities to Belarussians who lost their rights to study at home as punishment for opposition activities.
Earlier this year Sikorski also presided over a donors' conference in Warsaw — which Belyatsky attended — that raised millions of dollars for the Belarussian opposition.
Belyatsky is the leader of Vesna, the most prominent human rights group in Belarus. He was detained Aug. 4 and faces up to seven years in jail for helping political prisoners and government critics in Belarus.
Vesna said he has been charged specifically with "concealment of income." It said Belyatsky has received large amounts of cash in neighboring Lithuania from Western donors since the group was officially barred from receiving grants in Belarus.
The U.S. Embassy in Minsk condemned Belyatsky's detention as "another, unfortunate sign of Belarus' self-isolation and further deviation from European standards and principles."
Polish prosecutors said Friday that they were conducting an internal review to determine how the information got transferred to Minsk. They refused to comment further.