The Russian defence ministry says there were no serious casualties from the blasts on Tuesday in the northern Crimean village of Mayskoye, state-owned news agency RIA reported.
The agency also reported a fire at a transformer substation 20 kilometres away.
The Crimean peninsula on the Black Sea, which Russia seized and annexed from Ukraine in 2014 in a move not recognised by most countries, is the base of Russia's Black Sea Fleet and popular in the summer as a holiday resort.
Last week, blasts at a military air base in the city of Novofedorivka, on Crimea's western coast, caused extensive damage and destroyed several Russian warplanes.
Moscow called that an accident, though simultaneous blasts at several parts of the base had left craters visible from space.
Ukraine has not officially confirmed or denied responsibility for explosions in Crimea, though its officials have openly cheered incidents in territory that, until last week, appeared safe in Moscow's grip beyond range of attack.
"A reminder: Crimea of normal country is about the Black Sea, mountains, recreation and tourism, but Crimea occupied by Russians is about warehouses explosions and high risk of death for invaders and thieves," Ukrainian presidential adviser Mykhailo Podolyak tweeted after the reports from Mayskoye.
Kyiv aims to disrupt Russian supply lines ahead of a planned Ukrainian counterattack. Mayskoye is on the main railway line linking Crimea with Russia, and used to supply Russian forces in southern Ukraine.
Like the air base, it is out of the range of the main rockets Western countries acknowledge providing Ukraine so far, suggesting that if the explosions were some form of attack, Kyiv has acquired capability to strike deeper into Russian territory.
With the war raging since February 24, attention has also focused in recent days on shelling in the vicinity of the Zaporizhzhia nuclear plant in southern Ukraine. Both sides have blamed each other for risks to Europe's largest nuclear facility, which Russia has seized though Ukrainian technicians operate it.
Ukrainian President Volodymyr Zelenskiy has accused Russia of using the site as a shield for attacks and risking a nuclear catastrophe. He wants new sanctions on Moscow's nuclear sector.
Russian officials say it is their enemies who are shelling.
Reuters could not immediately verify battlefield reports.
The nearly six-month conflict has caused millions to flee, killed thousands, and deepened a geopolitical rift between Moscow and the West.
Russia calls its invasion a "special military operation" to demilitarise its neighbour, protect Russian-speaking communities and push back against the NATO military alliance's expansion.
Ukraine and Western backers accuse Russian President Vladimir Putin of waging an imperial-style war of conquest.
Putin accused the United States of trying to "drag out" conflict in Ukraine by supporting the Zelenskiy government. Washington also wanted to extend a "NATO-like system" into the Asia-Pacific region after "a thoroughly planned provocation" with US House of Representatives Speaker Nancy Pelosi's visit to Chinese-claimed Taiwan this month, Putin told a conference.
Even as the biggest attack on a European state since 1945 ground on, there was progress on a grain deal to ease a global food crisis created by the conflict.
The ship Brave Commander left the Ukrainian port of Pivdennyi, carrying the first cargo of humanitarian food aid bound for Africa from Ukraine since Russia's invasion.
Ukraine's grain exports have slumped because of the closure of its Black Sea ports, driving up global food prices and sparking fears of shortages in Africa and the Middle East.
On the battlefield, the sides reported no major changes to positions.
Ukraine reported continued Russian shelling and rocket attacks in the Donbas eastern area, and success in repelling attempted Russian advances near the Lysychansk oil refinery in the Luhansk region of the Donbas.
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