A powerful explosion that set a chemical plant on fire in eastern Ukraine was blamed on a careless "dropped cigarette butt" by Kiev officials, but pro-Russian rebels say they were attacked by the Ukrainian military.
The plant is in the separatist stronghold of Donetsk near where Malaysian Airlines flight MH17 was shot down last year.
Footage shows a fireball shooting into the sky above the plant after the explosion was triggered.
A spokesman for Kiev's Anti-Terrorist Operation said the explosion was the fault of the rebels because of poor safety procedures, 9 News reports.
"This was caused by a dropped cigarette butt. Accidents often happen in factories where no one is responsible for fire safety. Well, it's chaos, and they are barbarians," the spokesman said.
Officials from the Donetsk People's Republic, who control the area where the incident occurred, said they were attacked and said it was most likely a high-calibre artillery shell.
Ukrainian politician Dmitry Yarosh also said on his Facebook page that the military had launched the attack.
There were no reported casualties or injuries.