The International Criminal Court (ICC) has issued an arrest warrant for Russian President Vladimir Putin, accusing him of the war crime of illegally deporting hundreds of children from Ukraine.
The move will obligate the court's 123 member states to arrest Mr Putin and transfer him to The Hague for trial if he sets foot on their territory.
Moscow has repeatedly denied accusations that its forces have committed atrocities during its one-year invasion of its neighbour and the Kremlin branded the court decision as "null and void".
Neither Russia not Ukraine are members of the ICC, although Kyiv granted it jurisdiction to prosecute crimes committed on its territory. The tribunal has no police force of its own and relies on member states to make arrests.
Ukraine's President Volodymyr Zelensky hailed the "historic" decision of the ICC to issue the arrest warrant for Mr Putin.
"A historic decision from which historic responsibility will begin," Mr Zelensky said on social media.
Kremlin spokesman Dmitry Peskov said Russia found the very questions raised by the ICC "outrageous and unacceptable".
Asked if Mr Putin now feared travelling to countries that recognised the ICC, Mr Peskov said: "I have nothing to add on this subject. That's all we want to say."
Stephen Rapp, US Ambassador-at-Large for War Crimes Issues under former president Barack Obama, said: "This makes Putin a pariah. If he travels he risks arrest. This never goes away. Russia cannot gain relief from sanctions without compliance with the warrants."
Mr Putin is the third serving president to be the target of an ICC arrest warrant, after Sudan's Omar al-Bashir and Libya's Muammar Gaddafi.
Deportation of children
In its first warrant for Ukraine, the ICC called for Mr Putin's arrest on suspicion of unlawful deportation of children and unlawful transfer of people from the territory of Ukraine to the Russian Federation since 24 February 2022.
"Hundreds of Ukrainian children have been taken from orphanages and children's homes to Russia," ICC chief prosecutor Karim Khan said in a statement.
"Many of these children, we allege, have since been given up for adoption in the Russian Federation," he said.
The alleged acts "demonstrate an intention to permanently remove these children from their own country. At the time of these deportations, the Ukrainian children were protected persons under the Fourth Geneva Convention".
Mr Khan said his office will continue looking for additional suspects and "will not hesitate to submit further applications for warrants of arrest when the evidence requires us to do so".
Ukraine's top prosecutor, Andriy Kostin, hailed the ICC move as "a historic decision for Ukraine and the entire international law system".
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European Union foreign policy chief Josep Borrell said it was just the start of "holding Russia accountable for its crimes and atrocities in Ukraine".
Some Russians saw the hand of the United States in the ICC decision, although Washington, like Moscow, is not a state party.
"Yankees, hands off Putin!" wrote parliament speaker Vyacheslav Volodin, a close ally of the president, on Telegram, saying the move was evidence of Western "hysteria".
"We regard any attacks on the President of the Russian Federation as aggression against our country," he said.
The court has also issued a warrant for Maria Lvova-Belova, Russia's Commissioner for Children's Rights, on the same charges. She responded to the news with irony, according to RIA Novosti agency.
"It's great that the international community has appreciated the work to help the children of our country."
Ukraine has said more than 16,000 children have been illegally transferred to Russia or Russian-occupied territories in Ukraine.
A US-backed report by Yale University researchers last month said Russia has held at least 6,000 Ukrainian children in at least 43 camps and other facilities as part of a "large-scale systematic network".
Russia has not concealed a programme under which it has brought thousands of Ukrainian children to Russia, but presents it as a humanitarian campaign to protect orphans and children abandoned in the conflict zone.
The ICC's Mr Khan opened the investigation into possible war crimes, crimes against humanity and genocide in Ukraine a year ago. He highlighted during four trips to Ukraine that he was looking at alleged crimes against children and the targeting of civilian infrastructure.
Earlier today, Russia said that all fighter jets supplied to Ukraine by Western nations would be destroyed, after NATO members Poland and Slovakia pledged to send MiG-29 jets to Kyiv.
Since Russia's invasion last year NATO countries have sent billions of dollars of military aid to Ukraine, as Kyiv asks for weapons it says are vital to fend off Russian advances.
Moscow has accused the West of directly participating in the conflict through supplying weapons to Ukraine, and has warned before that NATO weapons were legitimate targets for its forces.
"In the course of the special military operation all this equipment will be subject to destruction," Kremlin spokesman Dmitry Peskov told reporters.
"It feels like all of these countries are thus engaged in the disposal of old unnecessary equipment," he said.
Slovakia will donate 13 MiG-29 warplanes to Ukraine, making it the second NATO member to announce such a shipment following a similar move by Poland.
"We will hand over 13 of our MiG-29 jets to Ukraine," Slovak premier Eduard Heger said, adding that Bratislava would also deliver a Kub air defence system to Ukraine.
Ukraine has long requested fighter jets from Western allies, although seeking primarily modern US-made F-16s.
"Our steps are fully coordinated with Poland and Ukraine," Mr Heger said, adding that his government "stands on the right side of history".
The Kremlin in response said the fighter jets given to Ukraine would be destroyed, and repeated that Western arms deliveries to Kyiv would not change Russia's military aims.
"The supply of this military equipment - as we have repeatedly said - will not change the outcome of the special military operation... Of course, all this equipment will be destroyed," Mr Peskov said, using the official Russian term for Moscow's military intervention.
Polish President Andrzej Duda on Thursday announced that Warsaw would send four Soviet-made MiG-29 jets to Ukraine "in the coming days".
Slovak Defence Minister Jaroslav Nad said the transfer of MiGs from Slovakia to Kyiv will take "a couple of weeks".
The Slovak batch will include 10 operational MiG-29 fighter jets and an additional three that have not been operational since 2008.
Slovakia also has one other Mig-29 that will be placed in a military museum at home.
Slovakia plans to replace the jets with American F-16s. The changeover should take place no later than January 2024.
Meanwhile, Chinese President Xi Jinping will travel to Russia next week to hold talks with President Vladimir Putin.
Mr Xi's trip on 20-22 March comes after China last month published a 12-point plan for "a political resolution of the Ukraine crisis" and after a senior Chinese diplomat called yesterday for negotiations in a call with Ukraine's foreign minister.
The plan calls for the protection of civilians and for Russia and Ukraine to respect each other's sovereignty.
However, the United States and NATO have said Beijing's efforts to mediate are not credible as it has refrained from condemning Russia's invasion of Ukraine, which Moscow calls a "special military operation".
Chinese foreign ministry spokesperson Wang Wenbin said Mr Xi's visit to Russia - his first in nearly four years - was in part to promote "peace", although he made no explicit mention of the Ukraine war.
He said the leaders would also exchange opinions on major regional and international issues, strengthen bilateral trust and deepen economic partnerships.
The Kremlin said in a statement that Mr Xi and Mr Putin would discuss "topical issues of further development of comprehensive partnership relations and strategic cooperation between Russia and China". The statement also made no mention of Ukraine.
Mr Xi will hold a telephone call with Ukrainian President Volodymr Zelensky following his Russia visit, according to some media reports. Beijing has not confirmed the call.
China and Russia announced a "no limits" partnership in February 2022 when Mr Putin visited Beijing for the opening of the Winter Olympics, days before he sent tens of thousands of troops into Ukraine, triggering the biggest conflict seen in Europe since World War Two.