Hundreds of opponents of the Belarus President Alexander Lukashenko have held a second night of demonstrations in the capital, Minsk.
The protesters were mainly young people and students
Three opposition leaders were said to be among at least 30 people arrested in clashes with police.
One of the opposition leaders is said to be in hospital after being beaten.
The protesters say a referendum held on Sunday which allowed Mr Lukashenko to stand for a third consecutive term as president was fraudulent.
'No to tyranny'
The mostly young demonstrators marched on the presidential residence, waving banners reading "No to tyranny", when the clashes broke out.
United Civic Party leader Anatoly Lebedko was said to have been rushed to hospital suffering from a fractured skull, broken ribs and a blood clot in his liver.
"He was beaten severely, he was bleeding and in bad shape, but emergency medical personnel weren't allowed to treat him," United Civic Party deputy chairman Alexander Dobrovolsky told the AFP news agency.
"The commander of the riot troops ordered he be hit," he added.
Two other opposition leaders, Nikolai Statkevich and Pavel Severinets, were also arrested, the Interfax news agency reported.
An Associated Press photographer, Sergei Grits, was also detained.
More than 1,000 people demonstrated against the results on Monday.
They clashed with police and accused Mr Lukashenko of being a dictator.
Foreign observers in Belarus have criticised Sunday's referendum and parliamentary elections.
The Organisation for Security and Cooperation in Europe said the referendum fell significantly short of democratic norms.
The president has run the ex-Soviet republic since 1994.