The U.S.-financed and Minsk-based group Partnership is an NGO promoting democracy and the development of civil society.
KGB officers arrested four members of Partnership last week.
Meanwhile, the main opposition candidate Alyaksandr Milinkevich vowed today to use "appropriate measures" if authorities resorted to force to break up a rally planned for 2 March. He gave no explanation of what these measures might be.
Belarusian President Alyaksandr Lukashenka is running for a third term in the election. He has been widely accused of harassing the opposition and limiting its access to the media.
MEET THE CANDIDATES: Read brief biographies of the four candidates in the March 19 election.