Russia, whose leader is accused of war crimes, assumed charge of the United Nations Security Council on Saturday causing fury in Ukraine, with President Volodymyr Zelenskiy calling it an absurd and destructive move.

The last time Russia held the rotating presidency of the body responsible for maintaining peace and combating acts of international aggression was in February 2022 when Moscow troops launched a full-scale invasion of Ukraine.

“Unfortunately, we … have some obviously absurd and destructive news,” Zelenskiy said in his daily video address, adding that Russian shelling had killed a five-month-old boy on Friday.

“And at the same time Russia is chairing the U.N. Security Council. It’s hard to imagine anything that proves more the total bankruptcy of such institutions,” he said.

The presidency rotates alphabetically each month among the 15 members. Although it is largely procedural, the Kremlin and other Russian officials vowed to “exercise all its rights” in the role.

The United States on Thursday urged Russia to “conduct itself professionally” when it assumes the role, saying there was no means to block Moscow from the post.

In March, the International Criminal Court (ICC) – an international justice body not associated with the UN – issued an arrest warrant for President Vladimir Putin and his commissioner for children rights, accusing them of the war crime of illegally deporting hundreds of children from Ukraine.

Ukraine’s Foreign Minister Dmytro Kuleba called Russia’s presidency of the Security Council a “slap in the face to the international community.” Zelenskiy said it was time for a general overhaul of global institutions, including the Security Council.

“Reform is obviously necessary to prevent a terrorist state – and any other state that wants to be a terrorist – from destroying the peace,” he said.

Some 400 days into the war, which has killed thousands, destroyed Ukrainian cities and set millions of civilians to flight, Russia continues to take over parts of the country, pressing on with its assault in the east.

Earlier, Zelenskiy advisor Andriy Yermak also hit out at Iran, which Kyiv and its allies accuse of supplying Russia with arms. Tehran denies it is giving weapons to Russia.

“It is very telling that on the holiday of one terror state – Iran – another terror state – Russia – begins to preside over the U.N. Security Council,” Yermak wrote on Twitter, referring to Iran’s Islamic Republic Day holiday.