KYIV, UKRAINE • Ukraine’s air force said Wednesday that nine Russian warplanes were destroyed in a deadly string of explosions at an air base in Crimea, amid speculation the blasts were the result of a Ukrainian attack that would represent a significant escalation in the war.

Russia denied aircraft were damaged in Tuesday’s blasts — or that any attack took place. Ukrainian officials stopped short of publicly claiming responsibility for the explosions, while mocking Russia’s explanation that a careless smoker might have caused ammunition at the Saki air base to catch fire and blow up.

Analysts also said that explanation doesn’t make sense and that the Ukrainians could have used anti-ship missiles to strike the base.

If Ukrainian forces were, in fact, responsible for the blasts, it would be the first known major attack on a Russian military site on the Crimean Peninsula, which was seized from Ukraine by the Kremlin in 2014.

Russian warplanes have used Saki to strike areas in Ukraine’s south.