Around 400 people have marched in Minsk to mark the anniversary of the 1986 Chernobyl nuclear power plant disaster, and protest against the construction of a nuclear plant in Belarus.
Wednesday was the 31st anniversary of the explosion and fire at the nuclear plant in neighbouring Ukraine.
The disaster spewed fallout-contaminated smoke over a wide area of northern Europe.
About a quarter of Belarus' territory was contaminated and an 850-square-mile region was declared unfit for human habitation.
The demonstrators said authorities are increasingly allowing crops to be grown on contaminated land. They also urged authorities to stop the construction of a nuclear plant which is due to open in 2019.
Unlike recent opposition rallies that saw hundreds arrested, Wednesday's march was sanctioned by authorities.