An ammunition depot exploded in northern Crimea, Russia's TASS news agency reported on Tuesday, citing the administration of the village of Mayskoye.
Russia's Defence Ministry said no "serious" casualties had occurred in the Mayskoye explosion, state-owned news agency RIA reported. Earlier on Tuesday, RIA also reported a fire at a transformer substation near the town of Dzhankoi in Crimea, 20 km (14 miles) away.
Crimea, which has been under Russian control since 2014 even as most of the world recognises it as Ukrainian territory, has been a major staging post for the military campaign Russia launched in Ukraine on February 24.
Ukraine has not officially confirmed or denied responsibility for reported explosions in Crimea in recent days.
"A reminder: Crimea as a normal country is about the Black Sea, mountains, recreation and tourism, but Crimea occupied by Russians is about warehouse explosions and high risk of death for invaders and thieves," Ukrainian Presidential advisor Mykhailo Podolyak tweeted after Tuesday's explosions.
The Russian reports did not say how many blasts occurred in total.
Last week, a series of explosions at a military air base in the city of Novofedorivka, on Crimea's western coast, appeared to cause extensive damage and destroy several Russian military aircraft, according to commercial satellite photos. Russia called the incident an accident.