Belarusian authorities have enforced tight security measures in Minsk to prevent an opposition rally marking the anniversary of the Chernobyl nuclear disaster.
Military and police forces flooded the center of the Belarusian capital on April 26, blocking central avenues to thwart the march. Police arrested about 20 people, according to the Vyasna human rights group.
The actions were part of an ongoing brutal crackdown on protests that began after a disputed reelection in August that gave strongman Alyaksandr Lukashenka a sixth term, a vote that the opposition says was rigged.
Crisis In Belarus
Read our coverage as Belarusians continue to demand the resignation of Alyaksandr Lukashenka amid a brutal crackdown on protesters. The West refuses to recognize him as the country's legitimate leader after an August 9 election considered fraudulent.
Lukashenka's clampdown has included thousands of detentions. Some of the protesters detained have reported beatings and other rights abuses. Some 350 political prisoners remain behind bars, according to Vyasna.
The clampdown has also included a massive security presence to dissuade protests and restrictions on journalists trying to report about the movement to oust Lukashenka.
Earlier on April 26, several dozen women dressed in black and carrying black umbrellas staged a demonstration on the outskirts of the capital. There were no detentions at that demonstration, although it was not authorized.
The women tied long yellow-and-black ribbons on their wrists and wore face masks with the yellow-and-black symbol for nuclear power. They marched in the Malinauka district, an area nicknamed Chernobyl because people who left areas of Belarus affected by radiation from the accident were given apartments there.
The Belarusian opposition has accused the authorities of concealing the true scope of the Chernobyl disaster, which contaminated large areas in Belarus.
An explosion and fire caused by a reactor meltdown at the Chernobyl power plant located 110 kilometers north of Kyiv on April 26, 1986 sent radiation across much of Europe.
In years past, the opposition in Belarus marked the anniversary with marches, reflecting the damage the country has suffered, including a suspected increase in the rate of cancer.
Lukashenka marked the anniversary this year by taking part in a requiem rally in the town of Bragin, southeast of Minsk.
Opposition leader Svyatlana Tsikhanouskaya, who left Belarus after the election for security reasons, spent April 26 meeting with ambassadors of the Organization for Security and Cooperation in Europe (OSCE).
"We discussed the effective use of the OSCE mechanisms for new free & fair elections in Belarus and the solidarity of the global community with Belarusians," Tsikhanouskaya said on Twitter.