Earlier in the day, Pashinyan's opponents blocked several of the city's central streets and avenues.
"According to the information provided to the media by the police, 28 people have been brought to police stations. However, by comparing information, we have determined that their number is 34," the movement said in a statement.
On Friday, Pashinyan posted a statement on Facebook saying that he is inviting parliamentary and non-systemic influence groups to discuss his proposal for snap elections next year, and that he is ready to resign if it is the "people's decision".
The country has been rocked by protests in the wake of Pashinyan signing the agreement with Azerbaijan on ending hostilities in the breakaway republic of Nagorno-Karabakh, which is viewed as a defeat for Armenia in the prolonged conflict.
The opposition has proposed former Prime Minister Vazgen Manukyan to assume office in Pashinyan's stead.