Russia becoming president of the United Nations Security Council is a "stark reminder that something is wrong with the way international security architecture is functioning," Ukraine's foreign minister has said.
On Saturday, Russia took over from Mozambique as the leader of the United Nation's top body.
Each of the body's 15 members assumes the presidency for a month, on a rotating pattern.
Russia's presidency means the Council - which is responsible for maintaining international peace and security - is now headed by a country whose president is subject to an international arrest warrant for alleged war crimes.
Dmytro Kuleba, Russia's foreign minister tweeted on Saturday: "Russian presidency in the UNSC is a stark reminder that something is wrong with the way international security architecture is functioning.
"A state that systemically ruins international peace and security will be presiding over the body tasked with maintaining them."
As Security Council president, Russia will be responsible for setting the agenda for the month, organising meetings, managing the distribution of information to Council members, issuing statements, and communicating the Council’s actions to the public.
Ahead of assuming the presidency, Moscow said it would hold an informal meeting of the Council in early April.
The country's UN ambassador Vassily Nebenzia said last week that the meeting will centre on “the real situation” of Ukrainian children taken to Russia, an issue that has gained the spotlight following the International Criminal Court’s arrest warrant for President Putin for war crimes related to their abduction.
The court said it was seeking Putin’s arrest because he “is allegedly responsible for the war crime of unlawful deportation of (children) and that of unlawful transfer of (children) from occupied areas of Ukraine to the Russian Federation”.
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Mr Nebenzia called the issue of the children “totally overblown” and said Moscow wants to explain at the Security Council meeting, around April 6, that they were taken to Russia “simply because we wanted to spare them of the danger that military activities may bring”.
China, France, Russia, the United Kingdom and the United States are permanent, veto-wielding members of the Security Council.
Its 10 other members are elected by the 193-nation General Assembly for staggered, two-year terms. They’re allocated by global regions.
The council deploys peacekeeping missions, can approve sanctions and speaks out - sometimes - on conflicts and flashpoints, while also surveying such thematic issues as terrorism and arms control.
While many matters are perennials on the agenda, council members also can use the platform to spotlight emerging concerns or topics of particular interest to them.