The leaflets contained the text of an address by poet Uladzimir Nyaklyaeu, the leader of the Tell the Truth campaign, to young people. Nyaklyaeu's speech was called "The Right Choice for the Right Path."
The activists were detained at Belarusian State University, Linguistics University, and Economics University.
One of the activists, Mikhas Pashkevich, told RFE/RL after being released that university security guards refused to tell him why it is illegal to distribute the leaflets.
University security guards told RFE/RL that they had to call police in order to stop "disruption on the university's premises."
Yury Aleinik told RFE/RL that he and the other activists had managed to distribute more than 3,000 of the leaflets.
The Tell the Truth campaign encourages Belarusians to speak out about a range of social ills.