How did Ukraine strike deep inside Russian-occupied Crimea?

How did Ukraine blow up Russia’s Saki Air Base in southwest Crimea on Tuesday? Was it with supersonic ballistic missiles, perhaps made in the United States? Or did it send a SEAL Team 6-style special ops, dropped deep behind enemy lines, to set explosions?

Whatever it was, Ukrainians on social media haven’t been this excited since their military sank the Moskva, the flagship cruiser of Russia’s Black Sea Fleet, in April. As many as nine Russian warplanes were annihilated on Tuesday, according to Ukraine’s Air Force.

Russian soldiers, notoriously disguised as “little green men,” invaded Crimea in March 2014, weeks after protests in Kyiv erupted over Ukraine’s then-President Viktor Yanukovych’s about-face on further integrating the country with the European Union. Russian President Vladimir Putin later acknowledged in a Russian documentary the stealth takeover and annexation of Ukraine’s peninsula on the Black Sea, which is about the size of Massachusetts. Since then, Crimea has been promoted on Russian state media much as it was during the Soviet era, as a popular summer seaside destination — within Russia.

The U.S., the EU and a host of other nations still recognize it as sovereign Ukrainian territory, while quietly acknowledging that its physical recapture by Kyiv is a long way off.

That is why the psychological impact of the attack on Saki Air Base may have packed the biggest bang.

Photographs have gone viral of discombobulated Russian holiday makers scrambling out of their cabana on the beach against the backdrop of a huge, dark plume of smoke, as have videos of a miles-long traffic jam of vacationers hurrying back to Russia along the only bridge system connecting the country to Crimea.

In one video, a Russian woman weeps from the back seat of her car: “I don’t want to leave Crimea. … How cool it is here.”

Even more delightful to Ukrainians is how Russian state media quickly dismissed the event, claiming the explosions were a result of “poor fire safety,” an explanation that Ukraine’s Ministry of Defense mocked by reiterating the “prohibition of smoking in unspecified places.”

Moscow’s denials that any aircraft were damaged in the subsequent fire also collapsed as quickly as Crimea’s tourist season.

An Su-24 fighter bomber shown lying on a blackened tarmac on Tuesday was clearly destroyed. And satellite imagery now confirms the extent of the devastation, which may be even greater than what Ukraine’s Air Force assessed. The base is littered with the burned-out husks of 15 to 20 costly Russian aircraft.

Saki Air Base was constructed in typical Soviet style, with hardened ammunition bunkers and blast-protected parking for each aircraft. The purpose of such measures was to minimize the effect of either an enemy attack or the kind of accident the Kremlin says just occurred. Yet satellite images of the base taken just days earlier show many of the blast-protected hardstands not being used. A number of Russian warplanes were simply parked next to one another on the airport’s apron.

A senior Ukrainian Ministry of Defense official confirmed Kyiv’s responsibility to Yahoo News within hours of the attack. “It’s just getting warmed up,” he said, indicating that more operations like this one are in the offing. But he wouldn’t say how. “I’m not ready to comment yet, sorry.” Which hasn’t stopped rampant speculation among analysts, journalists and casual war-watchers.

The attack took place at a considerable range from Ukrainian lines, about 180 miles. That fact alone would suggest that if a missile were to have been fired, it wasn’t something that was previously in the Ukrainian arsenal, or at any rate known to be. Defending forces have not demonstrated the capacity to strike at targets this far inside Russian-held positions before.

So maybe the Ukrainian military held onto its big ammo for six months. Or maybe the munition used was an indigenously developed weapons system that the Ukrainians have brought online since the start of the war. Or maybe it was something supplied by Western partners, unadvertised in public security assistance packages.

The most prominent outstanding request from Kyiv is the Army Tactical Missile System (ATACMS), a highly accurate tactical ballistic missile, which can be fired from any of the Multiple Launch Rocket Systems (MLRS) sent to Ukraine in the past months, including the much-celebrated U.S. M142 HIMARS. But at the Aspen Security Forum on July 22, U.S. national security adviser Jake Sullivan ruled out providing ATACMS to Ukraine, citing a fear of escalation with Russia, which might lead the United States to be “heading down the road towards a third world war.”

Could ATACMS have been sent to Ukraine covertly?

It’s possible but unlikely, given that the Russians could identify wreckage of the missile, prompting some awkward press conferences at the White House. However, there is precedent for the United States to supply sophisticated matériel to the Ukrainians that hasn’t been announced in any of the itemized Pentagon packages.

On Aug. 8, the Pentagon revealed the provision of AGM-88 HARMs missiles to Ukraine, sophisticated radar-hunting munitions that home in on signals emitted by air defense systems, destroying them, or at least forcing them to stop operating. The revelation followed visual evidence of the Russians’ recovering debris from an expended AGM-88 in the field.

The Ukrainians have also given messages — possibly deceptive — about the attack as part of their psychological warfare program. One unnamed official told the New York Times that “a device exclusively of Ukrainian manufacture was used” to pound Saki.

The most likely candidate among these systems would be the Hrim-2, a short-range ballistic missile that has been known to be under development in Ukraine but was not known to have reached operational status. With an on-paper range of over 300 miles and a 1,100-pound warhead, the missile has twice the destructive capability and a longer range than the most sophisticated ATACMS currently produced by the United States.

One issue, however: The Hrim-2 is not meant to be ready yet. That raises the intriguing possibility that the United States or another Western partner gave technical or financial assistance to get the project across the finish line. Thomas Theiner, a former artillery specialist in the Italian army, told Yahoo News that one major advantage the U.S. could provide to a domestic Ukrainian missile would be GPS guidance systems to improve its targeting accuracy.

“U.S. GPS guidance systems are so top-secret, the U.S. has sold them to no one,” Theiner said. “You can only get the missiles with the guidance kit installed.”

He added that Italy incorporated American GPS technology in its TESEO anti-ship missiles, but that this entailed U.S. engineers coming to Italy to install the guidance systems without allowing their Italian counterparts to look inside. “They only got the handbooks for the software. If the U.S. did the same with the Ukrainian Hrim-2, they’d ensure that any American tech would be destroyed upon impact and therefore unrecoverable by the Russians.”

Then again, maybe this attack wasn’t so high-tech after all.

The Washington Post cited an unnamed Ukrainian official it had interviewed who stated that Ukrainian special forces were responsible for the Saki sortie. If that’s true, then not only are Ukrainian commandos able to infiltrate Crimea by land, sea or air, but they can do so undetected and employ some form of loitering munition to carry out a major explosion. There was no audible gunfire or any reports of a firefight in the vicinity of Saki Air Base, nor any reports of casualties or POWs hinted at from either side. So that indicates that any Ukrainian special forces made it out all right, too.

Regardless of the weapon or tactic used by the Ukrainians to strike Saki Air Base, the very fact that they were able to do so considerably elevates Russia’s vulnerability on the battlefield. Ukraine hasn’t conducted any known military operations in Crimea since the unmarked Russian soldiers seized it in March 2014. That means that territory previously deemed safe for the occupiers is now demonstrably not so.

The Russians will not know how many munitions of similar capability the Ukrainians possess, and will therefore probably be compelled to adapt their force posture accordingly. At the very least, it seems probable that surviving high-value Russian fixed-wing assets, such as the Su-30SMs (price tag: $50 million) would be withdrawn to air bases farther away.

That will hinder Russia’s defensive capability in the forthcoming Ukrainian counteroffensive to recapture the port city of Kherson, the district directly north of Crimea.

Ukrainian President Volodymyr Zelensky and his military commanders have indicated that retaking Kherson, the first major city Russia occupied, in late February, is a top priority. Kyiv is said to be amassing a large army for that looming battle, which may begin by the end of the summer and last until winter. Not only is Kherson an important industrial hub, but taking the city and driving the Russians back across the Dnipro River would consolidate Ukrainian control of all the territory on the west bank, considerably shortening their defensive lines in the southern part of the country.

Whatever happens next, the last 48 hours have been embarrassing for Putin’s regime. Russian casualties are now estimated at between 70,000 and 80,000, with the military emptying jails and recruiting retirement-age soldiers for added manpower. Meanwhile, sanctions have taken a significant bite out of the Russian economy, so much so that the defense sector has started stripping commercial jets for parts, just to keep its air force in Ukraine aloft. Now comes a hastily canceled Russian summer at the beach, as memes of “Crimea river” and “National Lampoon’s Crimean Vacation” multiply on Twitter.