Dozens of demonstrators bearing lit candles have held a gathering in front of Belarus' KGB headquarters to commemorate victims of a Soviet mass execution and to protest continuing repression.

The Saturday demonstration was unsanctioned, but police did not interfere. It marked the 1937 killing of more than 100 members of the Belarusian intelligentsia on the orders of Soviet dictator Josef Stalin.

Anniversary gatherings held annually provide are a rare opportunity for public disapproval of the authoritarian leadership of President Alexander Lukashenko, who has stifled news media and opposition since coming to power in 1994.

Nikolai Statkevich, who ran against Lukashenko in the 2010 elections and was imprisoned for five years afterward, said: "The fear of repression haunts Belarus as before. Today's authorities are the ideological heirs of those times."