Gas-filled balloons exploded at a campaign rally in the Armenian capital of Yerevan on Friday, injuring 154 people.
Armenian authorities are working to identify what gas was used to blow up the balloons, RIA-Novosti reported, citing a statement by the country's emergency services ministry. The balloons were apparently not filled with helium or regular air, both of which are commonly used for the purpose and neither of which are explosive.
As a result of the explosion, 154 demonstrators standing near the balloons at a rally of the Armenian Republican Party received burns and were hospitalized. As of early Saturday, more than 70 people remained in the hospital, Interfax reported.
The rally took place in a central square in Yerevan ahead of parliamentary elections in Armenia scheduled for Sunday.
Armenian authorities are investigating whether the explosion was set off by someone purposefully or was an accident, a police spokesman told Interfax.