Supporters of former Foreign Minister Raffi Hovannisian rallied in his support in Yerevan after preliminary totals showed incumbent President Serzh Sargsyan won the majority of the vote in Monday's election.
Karin Woldseth, head of a European observer mission, said that while there was clear evidence of a successful vote, public trust was eroded because of alleged interference in favor of the incumbent.
British Minister for Europe David Lidington echoed those sentiments, saying the campaign was free and open and most Armenians took advantage of their right to vote.
"I welcome the International Election Observation Mission's preliminary report which concluded that the elections were characterized by a 'respect for fundamental freedoms' but also noted deficiencies in election administration and instances of political interference," he said in a statement.
Hovannisian met this week with Sargsyan, saying he'd discuss the outcome of that meeting during weekend rallies.
The U.S. and European governments expressed concern about political interference in statements this week.