The crowd of protesters led by MP Nikol Pashinyan continue their protest march along the central streets in capital Yerevan.
Sarksyan's ally Armen Sarkissian, a former premier and ambassador to Britain, was sworn in as president last week after being elected by parliament in a vote that was meant to herald the start of a power shift to the premier and parliament.
Protest leaders have vowed to hold demonstrations outside the building where Sarkisian is expected to be nominated. Some chanted "Armenia without Serzh" and "Serzh is a liar". On Monday morning, April 16, protesters blocked bridges, streets and underground stations to protest Sargsyan's candidacy.
The ruling Republican party nominated Sarksyan, who served as president for a decade from 2008, as its candidate for prime minister on Saturday. Several hundred people sat or laid down on pavements, blocking roads leading to the parliament building and universities.
"Something unprecedented is happening in Armenia - the same person wants to become the country's leader for a third time", Pashinian said at the weekend.
The protests were announced by the opposition Yelk (way out) coalition on 12 April, a day after Serzh Sargsyan's announcement, while lighting coloured smoke flares on the assembly floor of the Armenian parliament. Some built barricades using cast-iron benches and metal trash cans. The rallies began on Friday when more than 4,000 people took part. The two men are not related.