MINSK, Belarus (AP) — About 400 people have marched in Belarus' capital to mark the anniversary of the 1986 Chernobyl nuclear power plant disaster and protest the construction of a nuclear plant in the country.

Wednesday was the 31st anniversary of the explosion and fire at the nuclear plant in neighboring Ukraine. The disaster spewed fallout-contaminated smoke over a wide swath of northern Europe. About a quarter of Belarus' territory was contaminated and a 2,200-square-kilometer (85-square-mile) sector of Belarus 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 the nuclear plant, which will open in 2019.

Unlike recent opposition rallies that saw hundreds arrested, Wednesday's march in Minsk was sanctioned by authorities.