Former Russian President Dmitry Medvedev said on Monday that supplying American Tomahawk missiles to Ukraine could lead to severe consequences for everyone, especially for U.S. President Donald Trump.

Medvedev pointed out that it is impossible to distinguish between conventional Tomahawk missiles and those equipped with nuclear warheads once launched.

In a post on the Telegram app, Medvedev asked, “How should Russia respond? Exactly!” which appeared to hint that Moscow’s response would be nuclear.

Trump had warned on Sunday aboard Air Force One that Russia could face the deployment of long-range Tomahawk missiles to Ukraine if Moscow does not end the war in Ukraine soon, indicating he might be ready to increase pressure on Russian President Vladimir Putin using a significant weapons system.

Speaking to reporters aboard Air Force One en route to Israel, the U.S. president said, “I might tell them: Look, if this war doesn’t end, I will send them Tomahawk missiles.” He added, “Tomahawk is an amazing weapon, a very offensive weapon. Frankly, Russia doesn’t need that.”

He continued, “I might tell them that if the war doesn’t end – we might do it – we might not, but we might. I think it’s appropriate to put it out there.”

Trump’s remarks came after a phone call earlier Sunday with Ukrainian President Volodymyr Zelensky. The U.S. president said he mentioned the possibility of sending Tomahawk missiles during that conversation.

Trump said about Russia: “Do they want to see Tomahawk missiles going that way? I don’t think so.” He added, “I think I might talk to Russia about that.” He continued, “Tomahawk missiles are a new step of aggression.”

Putin himself had previously indicated that U.S. supply of long-range missiles to Ukraine would seriously damage Moscow-Washington relations.

Zelensky described his recent call with Trump as “very productive,” saying the two discussed strengthening “Ukraine’s air defense, its resilience, and long-range capabilities,” along with “details related to the energy sector.”