Thousands of people gathered in Armenia's capital Yerevan to protest the reelection of President Serzh Sarkisian.
Former Foreign Minister Raffi Hovannisian, who finished second in the February 18 election, told a rally of about 8,000 supporters that he would continue to push for an annulment of the vote.
Sarkisian was reelected to a second term with 58.6 percent of the vote, compared to nearly 37 percent for Hovanissian.
Hovanissian says the election was rigged.
He told protesters that the president, at a meeting on February 21, had rejected his demand for a rerun of the vote.
Hovannisian's supporters plan to hold protests against the election outcome on February 23 in the three cities -- Ashtarak, Gyumri and Vanadzor -- where Hovannisian won the vote.
Another protest is planned in Yerevan a day later.