US President Joe Biden has welcomed the International Criminal Court's issuing of an arrest warrant against his Russian counterpart, Vladimir Putin.
The ICC accused President Putin of committing war crimes in Ukraine - something President Biden said the Russian leader had "clearly" done.
Moscow has denied the allegations and denounced the warrants as "outrageous".
It is highly unlikely that much will come of the move, as the ICC has no powers to arrest suspects without the co-operation of a country's government.
Russia is not an ICC member country, meaning the court, located in The Hague, has no authority there.
However, it could affect Mr Putin in other ways, such as being unable to travel internationally. He could now be arrested if he sets foot in any of the court's 123 member states.
Mr Putin is only the third president to be issued with an ICC arrest warrant.
"He's clearly committed war crimes," he told reporters.
His administration had earlier "formally determined" that Russia had committed war crimes during the conflict in Ukraine, with Vice-President Kamala Harris saying in February that those involved would "be held to account".
The United Nations also released a report earlier this week that found Moscow's forced removal of Ukrainian children to areas under its control amounted to a war crime.
In a statement on Friday, the ICC said it had reasonable grounds to believe Mr Putin committed the criminal acts directly, as well as working with others. It also accused him of failing to use his presidential powers to stop children being deported.
Russia's commissioner for children's rights, Maria Lvova-Belova, is also wanted by the ICC for the same crimes.
ICC prosecutor Karim Khan has said the warrants were "based upon forensic evidence, scrutiny and what's been said by those two individuals".
The court had initially considered keeping the arrest warrants a secret, but decided to make them public to try and stop further crimes being committed.
"Children can't be treated as the spoils of war, they can't be deported," Mr Khan told the BBC.
"This type of crime doesn't need one to be a lawyer, one needs to be a human being to know how egregious it is."
Mr Khan also pointed out that nobody thought that Slobodan Milosevic, the Serbian leader who went on trial for war crimes in Croatia, Bosnia and Kosovo in the 1990s, would end up in The Hague to face justice.
"Those that feel that you can commit a crime in the daytime, and sleep well at night, should perhaps look at history," Mr Khan said.
Kremlin spokesman Dmitry Peskov said any of the court's decisions were "null and void" and former Russian President Dmitry Medvedev compared the warrant to toilet paper.
Russian opposition activists have welcomed the announcement. Ivan Zhdanov, a close ally of jailed opposition leader Alexei Navalny, has tweeted that it was "a symbolic step" but an important one.
Ukrainian President Volodymyr Zelensky has expressed his thanks to Mr Khan and the ICC for their decision to press charges against "state evil".