A Minsk-based human rights group says that more than four months ago Belarusian authorities executed a man who had been convicted of killing his own children.
The Vyasna (Spring) human rights center quoted the mother of the convicted man, Kiryl Kazachok, as saying that she was only informed in recent days that he was executed in October.
Amnesty International in January had mentioned Kazachok's case in a statement urging Belarusian President Alyaksandr Lukashenka to abolish capital punishment.
Kazachok was sentenced to death in December 2016 after a court in the southeastern city of Homel found him guilty of killing his 17-year-old son and 9-year-old daughter in order to punish his wife for wanting a divorce.
The court found that Kazachok was drunk when he carried out the killings.
Kazachok refused to appeal the sentence.
Belarus is the only country in Europe that carries out the death penalty.
The European Union and rights groups have for years been urging Belarus to declare a moratorium on the death penalty.
Activists say there are currently five convicted murderers on death row in Belarus.
In January, two men who initially were handed life sentences on murder charges were sentenced to death after a retrial in Minsk.
The EU sharply criticized Belarus at the time and repeated its call for Lukashenka's government to the abolish the death penalty.
According to rights organizations, more than 400 people have been sentenced to death in Belarus since the collapse of the Soviet Union in 1991.