Protests in Armenia continued for a fourth straight day on April 16, growing to an estimated 10,000 people and effectively shutting down Yerevan's downtown.
The source did not provide further details on the number of the detained opposition activists and the reasons behind their detention, claiming they obtain no such information.
Sarksyan's ally Armen Sarkissian was sworn in as president last week after being elected by parliament and in March Sarksyan said he would become prime minister to allow him to share the benefit of his experience.
But hours later he returned to the demonstration, bolstering his reputation among the thousands rallying against Sarkisian outside the legislature. The protesters also disrupted metro operations and stormed university campuses.
Sarkisian will remain the ex-Soviet country's leader under a new parliamentary system of government, which the opposition says has been created to maintain his chokehold on power.
"Serzh Sargsyan must see that he has no Armenia to rule in and no people to rule over".
"Our goal right now is to prevent Serzh Sarkisian from becoming the country's leader for a third time without violence and the use of force", said opposition leader Nikol Pashinian who led the protesters.
Rallies began on Friday when more than 4,000 people took part.
It is against the background of his nomination for Prime Minister, the Armenian opposition holds mass protests against the candidacy of Sargsyan.
A shrewd former military officer, Sargsyan has been in charge of the landlocked South Caucasus nation of 2.9 million since winning a presidential vote in 2008.
Sargsyan left the presidency this year upon reaching his term limit.
Authorities said 46 people, including six policemen, sought medical help. Serzh Sargsyan, who held the office for almost a decade, had promised he wouldn't seek the key job of prime minister.