Several hundred women gathered on the Independence Square of the Belarusian capital, ignoring calls to disperse.
In a comment to Sputnik, police have confirmed the detentions but refrained from specifying the number.
Belarus has been rocked by large-scale protests since the August 9 election, which saw President Alexander Lukashenko re-elected for a sixth term. The opposition rejected the outcome, claiming that Svetlana Tikhanovskaya won the election.
Thousands of protesters have been detained since the election, and opposition figures accuse the security forces of excessive violence during the peaceful demonstrations. Meanwhile, the government blames protests on foreign meddling.