Any attempt to arrest Vladimir Putin is war declaration on Russia, ally says.

Any attempt to arrest President Vladimir Putin after the International Criminal Court (ICC) issued a warrant for the Kremlin chief would amount to a declaration of war against Russia, his ally Dmitry Medvedev said on Thursday.

The ICC issued an arrest warrant on Friday, accusing Putin of the war crime of illegally deporting hundreds of children from Ukraine. It said there are reasonable grounds to believe that Putin bears individual criminal responsibility.

Former President Dmitry Medvedev told Russian media that the ICC, which countries including Russia, China and the United States do not recognize, was a “legal nonentity” that had never done anything significant.

Any attempt to detain Putin, though, would be a declaration of war, said Medvedev, who serves as deputy chairman of Putin’s powerful security council.

“Let’s imagine – obviously this situation which will never be realized – but nevertheless lets imagine that it was realized: The current head of the nuclear state went to a territory, say Germany, and was arrested,” Medvedev said.

“What would that be? It would be a declaration of war on the Russian Federation,” he said in a video posted on Telegram. “And in that case, all our assets – all our missiles et cetera – would fly to the Bundestag, to the Chancellor’s office.”

The Kremlin says the ICC arrest warrant is an outrageously partisan decision, but meaningless with respect to Russia. Russian officials deny war crimes in Ukraine and say the West has ignored what it says are Ukrainian war crimes.

Russia’s Feb. 24 invasion of Ukraine has triggered the deadliest European conflict since the Second World War and the biggest confrontation between Moscow and the West since the 1962 Cuban Missile Crisis.

Relations with the West, Medvedev said, were probably at the worst point ever.

As president from 2008 to 2012, Medvedev cast himself as a pro-Western reformer. Since the war, though, he has turned into one of the most publicly hawkish Russian officials, insulting Western leaders and delivering a series of nuclear warnings.

Nuclear risks had risen, he said.

“Every day’s delivery of foreign weapons to Ukraine brings closer the nuclear apocalypse,” Medvedev said.

After the 1991 fall of the Soviet Union, he said, the West had considered itself the boss of Russia but Putin had put an end to that.

“They were very offended,” Medvedev said, adding that the West disliked the independence of Russia and China.

He said the West now wanted to crack Russia apart into a host of weaker states and steal its vast natural resources.

Putin casts the conflict in Ukraine as an existential struggle to defend Russia against what he sees as an arrogant and aggressive West which he says wants to cleave Russia apart.

The West denies it wants to destroy Russia and says it is helping Ukraine defend against an imperial-style land grab. Ukraine says it will not rest until all Russian soldiers are ejected from its territory.

“Ukraine is part of Russia,” Medvedev said, adding that almost all of modern-day Ukraine had been part of the Russian empire. Russia recognized Ukraine’s post-1991 sovereignty and borders in the 1994 Budapest Memorandum.

Medvedev said ties with the West would one day improve, though he said it would take a long time.

“I believe that sooner or later the situation will stabilize and communications will resume, but I sincerely hope that by that time a significant part of those people (Western leaders) will have retired and some will be dead,” he said.