Vladimir Putin will be rattled by explosions in Crimea
Just a few weeks ago, Dmitry Medvedev, the deputy head of Russia's Security Council, promised to unleash "Judgment Day" if Ukraine ever attacked Crimea.
Now, Ukraine appears to have done just that - and the world is holding its breath for the Kremlin's response.
If it is proved to have been a Ukrainian attack, the Kremlin will constitute this as an attack on Russia itself.
So far, there have only been a handful of attacks on fuel and ammunition depots close to the border. This took place in sight of Russian holidaymakers in Crimea.
Western security said that if confirmed, the ultra-long-range of the strike would pose massive logistic and security problems for Russian commanders, who will now have to protect bases deep inside their own territory.
It is not clear exactly what else Moscow can do to amp up fighting in the war - Russian commanders already have plenty to worry about.
Since the start of July, US Himars and British M270 long-range artillery - which have a range of around 50 miles - have been hitting Russian supply lines, causing havoc and helping to shift the momentum of the war.
Ukraine’s military is now on the front foot.
It has stalled the Russian military’s momentum in Donbas and is threatening to launch its own major offensive to retake the Kherson region in the south of the country, a threat that has forced Russian military commanders to reportedly send 25,000 soldiers as reinforcements.
James Rushton, a British analyst based in Ukraine, said that the attack on the air base in Crimea was a watershed moment.
"A vast amount of territory they previously assumed safe, even from Himars and M270s, is now not," he said.
