STORY: Satellite images released on Thursday (August 11) show devastation at a Russian air base in Crimea.
The attack suggests Kyiv may have obtained new long-range strike weapons, capable of evading Russian defenses.
Such weaponry has the potential to change the course of the war.
The base is well beyond the range of advanced rockets that Western countries acknowledge sending to Ukraine so far, but within range of more powerful versions that Kyiv has sought.
Ukraine has not publicly claimed responsibility.
Some Ukrainian officials have been quoted suggesting it may have been sabotage by infiltrators.
But Western military experts say the scale of the damage and apparent precision suggest a powerful new capability.
Russia has denied aircraft were damaged and said explosions seen at the base on Tuesday were accidental.
In 2014, Russia annexed Crimea, which it uses as a base for its Black Sea fleet.
It’s the main supply route for invasion forces occupying southern Ukraine - where Kyiv is planning a counter offensive.
Ukraine wants to recapture the southern Kherson and Zaporizhzhia regions - the main slice of territory captured since the Feb. 24 invasion that Moscow still holds.
Russia maintains its "special military operation" is going to plan.