Rafi Hovannisian, the main challenger to Armenian President Serzh Sarkisian in the election in February, is currently in Moscow for a one-day visit.
Hovannisian's spokesperson, Ovsep Hurshudian, did not rule out that the Heritage Party leader would be holding official meetings before returning to Yerevan later on April 12.
Hovannisian, who officially lost to Sarkisian by roughly 20 points, has disputed the election results.
Hovannisian and opposition supporters on April 9 held an "alternative inauguration" as a counterpart to Sarkisian's official swearing-in for a second term in office.
Hovannisian has called Sarkisian's reelection "illegitimate."