KYIV, Ukraine • Powerful explosions rocked a Russian air base in Crimea and sent towering clouds of smoke over the landscape Tuesday in what may mark an escalation of the war in Ukraine. At least one person was killed and several wounded, authorities said.

Russia’s Defense Ministry denied the Saki base on the Black Sea had been shelled and said instead that munitions had blown up there. But Ukrainian social networks were abuzz with speculation that it was hit by Ukrainian-fired long-range missiles.

Videos posted on social networks showed sunbathers fleeing a nearby beach as huge flames and pillars of smoke rose over the horizon from multiple points, accompanied by loud booms. Crimea Today News said on Telegram that witnesses reported fire on a runway and damage to nearby homes as a result of what it said were dozens of blasts.

Russia’s state news agency Tass quoted an unidentified ministry source as saying the explosions’ primary cause appeared to be a “violation of fire safety requirements.” The ministry said no warplanes were damaged.

Ukraine’s Defense Ministry said sarcastically on Facebook: “The Ministry of Defense of Ukraine cannot establish the cause of the fire, but once again recalls the rules of fire safety and the prohibition of smoking in unspecified places.”

During the war, Russia has reported numerous fires and explosions at munitions storage sites on its territory near the Ukrainian border, blaming some of them on Ukrainian strikes. Ukrainian authorities have mostly remained mum about the incidents.

If Ukrainian forces were, in fact, responsible for the blasts at the air base, it would mark the first known major attack on a Russian military site on the Crimean Peninsula, which the Kremlin annexed in 2014.

A smaller explosion last month at the headquarters of Russia’s Black Sea Fleet in the Crimean port of Sevastopol was blamed on Ukrainian saboteurs using a makeshift drone.

Russian warplanes have used the Saki base to strike areas in Ukraine’s south on short notice. Crimea’s regional leader Sergei Aksyonov said ambulances and medical helicopters were sent to the base and the area was sealed off within a radius of 3 miles. One person was killed, Aksyonov said.

Crimean health authorities said nine people were wounded, one of whom remained hospitalized. Others were treated for cuts from shards of glass and released.

Officials in Moscow have long warned Ukraine that any attack on Crimea would trigger massive retaliation.