Two Belarusian activists who ran for president last year are on trial for organising mass protests.
Nikolai Statkevich and Dmitry Uss are charged in connection with a rally in the capital Minsk on Dec 19 where thousands of people protested against President Alexander Lukashenko and police rounded up hundreds of opposition supporters.
The crackdown led to Western sanctions which include a travel ban on Lukashenko and his associates.
Convictions for Statkevich and Uss could mean 15 years in jail. Several opposition activists have already been given prison terms of up to four years.
Lukashenko, who has been in power since 1994, won a fourth term in office last December in a vote that Western observers criticised as fraudulent.