The explosion in Yerevan stemmed from a cluster of balloons that blew up over the event.
Officials said they suspect the balloons were filled with explosive hydrogen, instead of helium, and they ignited when someone lit a cigarette nearby.
According to reports, none of the injuries appear to be life threatening.
The balloons were supposed to be flown at a Republican Party rally that drew tens of thousands ahead of Sunday's parliamentary vote in the former Soviet republic. Despite the accident, Armenian President Serge Sarkisian addressed the rally with a speech.
The Republican Party dominates the parliament of this impoverished Caucasus nation that borders Turkey.
The Associated Press contributed to this report.
