Ukraine’s defense minister refused to comment on whether his army was involved in explosions at an ammunition depot in Crimea, saying at a press conference in Copenhagen on Wednesday that they were caused by cigarettes, AFP reported.

“I think that the Russian military at this airfield forgot a very simple rule: ‘do not smoke in dangerous places.’ That’s it,” said Oleksiy Reznikov, who is visiting Denmark for a meeting with donor countries for Ukraine under the auspices of the Scandinavian country and the United Kingdom.

Bombings at an ammunition depot located at a military airfield in the Russian-annexed Ukrainian peninsula of Crimea on Tuesday killed and injured two people.

The Russian military said there was no shooting or bombing behind the explosions, which were first reported by the peninsula’s authorities.

Answering a question on this topic, the British Defense Minister said that he does not comment on this incident, but reminded Ukraine of its right to defend its territory.

“If this was an attack by Ukraine, it would be legitimate, it would be in accordance with international law,” said Ben Wallace.