Several thousand supporters of the Belarusian opposition have marched through the capital to mark the anniversary of the Chernobyl nuclear accident.
Demonstrators took to the streets of Minsk on Saturday protestesting against an alleged government cover-up of the disaster's consequences.
The Chernobyl nuclear power plant in Ukraine is just south of the border with Belarus.
On April 26, 1986, one of the plant's reactors exploded, spewing a cloud of radiation over much of Europe - and Belarus, downwind from the plant, was severely affected.
In recent years, the government has taken about 1,000 cities and towns in the area off of the radiation danger list, despite what critics say is a substantial continuing health risk.
Statistics about illness in the contaminated parts of Belarus - about 23 per cent of its territory - are kept under wraps by the government of Alexander Lukashenko, the president.
The government says that the areas it has removed from the danger list are safe to return to.
Protesters said the government was denying help to people affected by the disaster, including those who were sent in to clean up radioactive fallout.
Valery Yagur, 56, a protester who had been among the clean-up workers, said: "The government has abolished our benefits in order to bury us and the problems together. Lukashenko is simply burying those people who liquidated the disaster."
"Lukashenko is simply burying those people who liquidated the disaster"
Valery Yagur, a protester
Lukashenko's government rarely allows opposition rallies, and participants took the opportunity of Saturday's sanctioned gathering to raise protests against his hardline rule.
They carried signs reading "Freedom" and the now-banned red-and-white flag that was the first flag of post-Soviet Belarus.
The demonstration was peaceful and ended without incident.
Konstantin Timokhov, 21, one of the protesters, said he was deeply worried that the government will force him to work in a contaminated area when he graduates from university.
"The government is hiding the truth from us. My health and my future are in danger," he said.
Radiation levels have declined substantially in most areas near Chernobyl, but scientists disagree on the level of risk.