The head of Sevastopol’s Civic Chamber, Alexander Formanchuk, has warned that if Ukraine attempts to recapture Crimea, a territory annexed by Russia in 2014, it will lead to a nuclear war.

In an interview with RIA Novosti, Formanchuk said, “Any attempt to seize Crimea and return it to Ukraine will immediately escalate into a thermonuclear global conflict. Russia will not forgive this.”

The comments from Formanchuk follow remarks from former CIA Director David Petraeus, who said Ukraine could retake Crimea. While speaking to the Washington Post, Petraeus said, “Here’s the scenario. If [Ukraine] can, in the spring/summer offensive this year, sever the ground link that Russia has, the ground bridge, as it’s called, that Russia has established that goes from Russia proper down into Ukraine, and so they block that, then, Russia is dependent on the Kerch Strait Bridge to keep Crimea resupplied. If you could take that down again—or part of it, of course, was knocked down earlier—and then force it to rely on ferries, and then if you can start taking them out—now, these are very, very challenging actions and operations. If you can isolate Crimea fully and if you then have the precision munitions with greater range and can start picking off the Black Sea Fleet headquarters, the various air bases, the various seaports, and all the rest of this, again, it is not inconceivable that you could sufficiently isolate it, and then at some point in time, either go in on the ground or have some kind of concession in the other direction.”

Formanchuk also said the former CIA director’s scenarios regarding Crimea were “suicidal” and reminded Washington and Kyiv of how Russia reacted to the attack on the Kerch Strait Bridge in October 2022. After the attack on the bridge, Russia launched a series of strikes on Ukraine’s critical infrastructure.

Despite this, Ukrainian President Volodymyr Zelensky has vowed to take back Crimea and has stated that Ukraine’s military has always kept this goal in mind. However, many fear retaking Crimea would be a red line for Russia and that Putin may use his country’s nuclear capabilities to defend the territory.