Ukrainian officials say an explosion inside a tram in the eastern city of Dnipropetrovsk has injured at least nine people.
The Interior Ministry said the explosion was caused by the “improper handling of gunpowder” by one of the tram passengers.
Officials said the 40-year-old owner of the gunpowder was among the nine people injured.
The man is reported to have obtained the gunpowder for use in fishing and hunting.
No link to terrorism is suspected, officials said.
On April 27, 31 people in Dnipropetrovsk were injured when four devices that had been placed in garbage bins exploded in what officials described as a terrorist attack.
Authorities have announced the arrests of four suspects over the April blasts, saying the men had tried to obtain money from the government.
Based on reporting by UNIAN and Interfax