Dozens of protesters rallying against former President Serzh Sarkisian's election as prime minister were arrested on Thursday.
Protesters held up a huge, upside-down official portrait of Sarkisian and shouted anti-government slogans.
Led by opposition MP Nikol Pashinyan, more than two thousand protesters marched towards government headquarters in the afternoon where a cabinet meeting was under way.
"Serzh Sarkisian...we came here to tell you that the people hate you!" Pashinyan shouted.
"Armenians are ready to fight for their future, we will not stop, our victory is imminent," 26-year-old protester Misak Mesropyan told AFP at the rally.
Another protester, pensioner Ruben, said: "Protests must continue if we want Serzh (Sarkisian) to finally step down."
The influential head of the Armenian Apostolic Church, Catholicos Garegin II, expressed concern over the political turmoil.
"Inciting hatred and enmity as well as any form of violence are unacceptable," he said in a statement.
New President Armen Sarkisian, who is not related to his predecessor, said in a statement he invited "all parties to start dialogue to find the best way out of the situation".
Earlier, several hundred demonstrators attempted to blockade the entrance to the government building before riot police intervened, arresting dozens and taking them to a local police station.
Controversial constitutional amendments approved in 2015 have transferred governing powers from the presidency to the premier.
Pashinyan -- who earlier announced the "start of a peaceful velvet revolution" –- has said the movement's objective is to bring about a change of leadership in Armenia through a nationwide campaign of civil disobedience.
But the number of demonstrators has dwindled, down from roughly 40,000 on Tuesday evening -- the largest protest Armenia has seen in years.
Sarkisian stepped down because of term limits, but he will continue to play the dominant role as prime minister under the new political system that envisages a mostly ceremonial role for president.
About 15,000 rallied Wednesday at Yerevan's central Republic Square under slogans: "Make a step and reject Serzh." Smaller protests also have swept Armenia's second-largest city of Gyumri and a few other cities.
Protests that began Friday have been mostly peaceful, except for Monday's clashes with police that left 46 people injured, including six police officers.
On Wednesday, police unblocked some of the streets cut by protesters and detained 84 demonstrators, according to police spokesman Ashot Agaronian. He said that 30 of those detained already have been released and would face administrative charges.
Protests began in Yerevan on Friday and have since spread to the country's second and third largest cities, Gyumri and Vanadzor.
A former military officer, Serzh Sarkisian, 63, has been in charge of the landlocked South Caucasus nation of 2.9 million people for a decade.
He also held the office of prime minister from 2007 to 2008.
After he was first elected in 2008, 10 people died and hundreds were injured in bloody clashes between police and supporters of the defeated opposition candidate.
