A huge fire at an ammunition depot in central Ukraine set off a series of explosions and prompted the evacuation of tens of thousands of people.
The country's prime minister, Volodymyr Groysman, hinted the cause was possible sabotage, saying the country was at war and expects that its enemies "will do all they can to make us weak".
The fire broke out late on Tuesday (26 September) at a military base near the town of Kalynivka, 190 kilometres (120 miles) southwest of the capital, Kiev.
Authorities evacuated 30,000 people from the town and turned off the electricity and gas supply.
One person was injured, Ukranian emergency services said.
The powerful explosions created massive fireballs that towered into the sky. Four residential buildings were damaged.
Local media reported that about 188,000 tonnes of munitions were kept at the depot, including rockets for the Grad multiple grenade launchers.
Andriy Ageyev, spokesman for the Ukrainian Defence Ministry, said munitions at the military base were still detonating late Wednesday morning.
Olena Gitlyanska, spokesman for the Ukrainian Security Service, told the Unian news agency that they were treating the fire as sabotage. She did not provide further details.
Speaking at an urgent session of the cabinet on Wednesday, Prime Minister Groysman also suggested it was possible sabotage was involved, saying that Ukraine was at war and that it expects that its enemies "will do all they can to make us weak".
Government forces have been fighting Russia-backed separatists in eastern Ukraine since April 2014 in a conflict that has left more than 10,000 dead and displaced more than a million.
President Petro Poroshenko has called for an urgent meeting of the country's top brass to discuss the situation.
In a similar incident in March, a fire at a military depot in Ukraine's east raged for hours and prompted the evacuation of over 20,000 people.