More than 1,000 Armenian opposition supporters have attended a protest in Yerevan following the end of the state of emergency imposed three weeks ago.
Mr Ter-Petrosian wants the election results overturned
The demonstrators lit candles and held pictures of the more than 100 activists who were arrested after clashes with police on 1 March left eight dead.
fighting erupted when officers tried to end a protest against the result of last month's presidential election.
The poll gave victory to the current Prime Minister, Serzh Sarkisian.
The opposition says there was widespread fraud and wants to result overturned.
Supporters of the main opposition leader, Levon Ter-Petrosyan, who came second, took part in the march in Yerevan on Friday, only hours after the state of emergency was lifted.
The procession was a peaceful vigil to remember the 106 opposition activists arrested since the clashes for allegedly plotting a coup.
No violence was reported, although several protesters shouted at riot police.
When announcing the end of the state of emergency, outgoing President Robert Kocharian warned that any unauthorised protests would not be tolerated.
A new law passed this week allows the authorities to ban demonstrations if they are said to be a threat to public order.
But the opposition says it has the right to protest and will find a way to work around the legislation.
The party of President-elect Sarkisian and three other parties have agreed to form a coalition government ahead of his inauguration on 9 April.