Protesters rallied outside a prison in Minsk on Tuesday where the husband of Belarus's main opposition figure is being held, as protests against disputed presidential elections entered their 10th day.
Several hundred people gathered outside the walls of the detention center to mark the 42nd birthday of Sergei Tikhanovsky, a popular blogger who was imprisoned alongside other rivals of longtime ruler Alexander Lukashenko ahead of the Aug. 9 election.
Holding red-and-white balloons in the colors of the opposition, the protesters clapped and chanted "happy birthday" to Tikhanovsky.
Tikhanovsky's wife, Svetlana Tikhanovskaya, was allowed to run in his place but fled to neighboring Lithuania after claiming victory in the fraught elections that sparked massive demonstrations and a brutal crackdown on street protests.
Belarus investigators have accused Tikhanovsky of inciting "social hostility" and calls to use violence against law enforcement officers.
In a video message on Tuesday, Tikhanovskaya said her husband was spending his birthday in prison accused of "a crime he did not commit."
"All of this blatant lawlessness and injustice shows how this rotting system works, in which one person controls everything, one person who has kept the country in fear for 26 years, one person who stole Belarusians of their choice," she said.
Tikhanovskaya, 37, has demanded the authorities release all detainees, remove security forces from the streets and open criminal cases against those who ordered the crackdown.
She has also said she will organize new elections if Lukashenko steps down.
The opposition has formed a Coordination Council to ensure a transfer of power, and it is due to convene Tuesday.
Belarus's 65-year-old authoritarian leader is coming under increasing pressure after days of protests and walkouts.
Lukashenko has dismissed calls to resign and rejected holding a new vote, telling protesters on Monday that "Until you kill me, there will be no elections."