Tens of thousands of demonstrators rallied Sunday in Minsk to begin the fourth week of daily protests demanding that the country’s authoritarian president resign.

Protesters initially tried to gather at Independence Square, but barriers and riot police blocked it off. They then streamed down one of the capital’s main avenues, past hulking olive-green prisoner transport vehicles. Police detained some marchers and forced them into the transports.

Police said 125 people were arrested, but Ales Bilyatsky of the Viasna human rights organization said more than 200 were detained.

The marchers, chanting “Freedom!” and “Resign!” eventually reached the outskirts of the presidential palace, which was blocked off by shield-bearing riot police. There were no official figures on the crowd size, but some opposition sources claimed it exceeded 100 000.