Permanent premises of the International Criminal Court in The Hague, the Netherlands. © 2018 Marina Riera/Human Rights Watch.

The International Criminal Court (ICC) has expressed concerns after a former Russian president threatened to strike the court following its issuing of an arrest warrant for President Vladimir Putin.

Ex-president Dmitry Medvedev on Monday threatened to bomb the war crimes tribunal with hypersonic missiles.

Russia’s top investigative body also opened a criminal case against ICC Prosecutor Karim Khan who issued the warrant for Putin, Al Jazeera reports.

Meanwhile, the ICC’s Assembly of States Parties said it “regrets these attempts to hinder international efforts to ensure accountability for acts that are prohibited under general international law”.

“The International Criminal Court embodies our collective commitment to fight impunity for the gravest international crimes. As an institution of last resort, the Court is complementary to national jurisdictions. We call on all States to respect its judicial and prosecutorial independence,” it added.

Medvedev, who is Vladimir Putin’s top ally and deputy chairman of the Security Council, previously issued a hypersonic missile attack threat.

Medvedev reportedly suggested that the ICC judges ‘watch the skies closely,’ referring to an impending missile coming their way.

“I’m afraid, gentlemen, everyone is answerable to God and missiles. It’s quite possible to imagine how a hypersonic Oniks fired from a Russian warship in the North Sea strikes the court building in the Hague,” he wrote on Telegram.

“It can’t be shot down, I’m afraid. And the court is just a pathetic international organisation, not the people of a NATO country. So, they won’t start a war. They’ll be scared. And no one will be sorry.”

President Putin and his human rights commissioner are wanted by the court for alleged war crimes in Ukraine including deporting children.