(CNN) -- Nearly half of those injured by exploding gas-filled balloons during a political campaign rally in Armenia's capital remained hospitalized on Saturday, according to state media. The incident occurred Friday in city of Yerevan, two days before parliamentary elections. The balloons erupted in flames, forcing at least 154 people to be hospitalized. By Saturday, medical personnel had still not discharged 76 of the victims, according to the official Armenpress. President Serzh Sargsyan reported that there were no fatalities as a result of the explosion, saying law enforcement has initiated an investigation, the agency said. "All those who are guilty will be revealed and punished in accordance with the law," Sargsyan said. "I urge everyone to keep calm. Let us pray for the injured and wish everyone fast recovery." The type of gas that filled the balloons is unclear. CNN's Karen Smith contributed to this report .
Gas-filled balloons exploded in the Armenian capital during a political campaign rally . 154 people were hospitalized after the incident . By Saturday, medical personnel had still not discharged 76 of the victims .