Thousands of civilians have been evacuated after an ammunition depot in Russian-annexed Crimea went up in flames, setting off a series of explosions.
Blasts were still being heard several hours after the fire was reported at the Kirovske military base on Wednesday morning, Russian media reported.
Authorities did not specify the cause of the blaze, but footage showed columns of black smoke billowing into the sky.
The incident came just days after an explosion on the Kerch bridge linking the Black Sea peninsula to mainland Russia, which the Kremlin has blamed on Ukraine.
Local authorities said more than two thousand people were evacuated from villages surrounding the depot. They were reportedly provided with temporary shelter.
Sections of the Tavrida highway, which connects Sevastopol to the Crimean port of Kerch, were closed, with vehicles redirected through regional roads.
Sergei Aksyonov, the Russian-backed head of Crimea, said: “In the Kirovske district, it is planned to temporarily evacuate residents of four settlements – this is more than two thousand people.
“An operational headquarters has been deployed, all specialised services are working on the spot.”
Vladimir Konstantinov, head of Crimea’s state council, appeared to suggest Ukraine was behind the attacks.
“The situation is dynamic. For the moment, everything is under control,” Mr Konstantinov said in a post on the Telegram messaging app.
“Kyiv is doing everything to shake up the situation inside Crimea. But they cannot understand that it all works in the opposite direction. Since 2014, we have been withstanding their provocations,” he added.
“Explosions at the training ground are still heard [at 12:45 local time]… In Crimea, there is experience in dealing with such situations.”
Early reports suggested Kylylo Budanov, the head of Ukraine’s military intelligence, had taken credit for the fire and hailed a “successful operation”.
However, this was later denied by the defence ministry and attributed to a fake post on Telegram.
Russia annexed Crimea from Ukraine in 2014 in a move not recognised by the international community.
Kyiv has repeatedly said it plans to take back the peninsula as part of its drive to expel Russian troops from its territory.
Separately on Wednesday, Ukraine accused Russia of having intentionally struck grain terminals and infrastructure in the Black Sea port of Odesa for a second consecutive night after Moscow quit a deal that allowed the safe export of Ukrainian grain to global markets.
“Russian terrorists absolutely deliberately targeted the infrastructure of the grain deal,” said Volodymyr Zelensky, the Ukrainian president, following Tuesday’s overnight attacks.
“Every Russian missile – is a strike not only on Ukraine but on everyone in the world who wants a normal and safe life.”
The Black Sea grain deal, agreed in July last year, was intended to combat a global food crisis worsened by Russia’s invasion of Ukraine and a blockade of Ukrainian ports.
Mr Zelensky has said the agreement could continue without Russian participation, and that Ukraine is working on options to keep its commitments on food supplies.
Russia announced on Monday that it was quitting the deal, complaining that promises to free up its own shipments of food and fertilisers had not been kept.