By Toby Sterling and Bart H. Meijer
THE HAGUE (Reuters) -Russian President Vladimir Putin must be brought to justice for his war in Ukraine, Ukrainian President Volodymyr Zelenskiy said on Thursday in The Hague, calling for the creation of a war crimes tribunal separate to the International Criminal Court.
"The aggressor must feel the full power of justice. This is our historical responsibility," Zelenskiy said in a speech.
"Only one institution is capable of responding to the original crime, the crime of aggression: a tribunal. Not some compromise that will allow politicians to say that the case is allegedly done, but a true, really true, full-fledged tribunal."
An act of aggression is defined by the United Nations as the "invasion or attack by the armed forces of a state (on) the territory of another state, or any military occupation".
The ICC, which is based in The Hague and which Zelenskiy visited earlier in the day, issued an arrest warrant for Putin for suspected deportation of children from Ukraine.
But it does not have jurisdiction over alleged crimes of aggression, and the European Commission, among others, has already brought its support for the creation of a separate international centre for the prosecution of the crime of aggression in Ukraine, that would be set up in The Hague.
"We all want to see a different Vladimir here in The Hague, the one who deserves to be sanctioned for his criminal actions here, in the capital of international law," Zelenskiy said, referring to Putin.
"I'm sure we will see that happen when we win, and we will win," he said, adding: "Whoever brings war must receive judgement."
Major legal and practical questions remain around how such a court would be legitimised, either by a group of countries supporting it or with approval from the U.N. General Assembly.
Russia is not a member of the ICC and already rejects its jurisdiction. It denies committing atrocities during its conflict with Ukraine, which it terms a "special operation" to "demilitarise" its neighbour.
Earlier in the day, in his first official visit to the Netherlands, Zelenskiy visited the ICC for just under an hour.
As he left, Zelenskiy, dressed in his trademark khaki, waved at a Ukrainian family standing outside the ICC building as they shouted "Slava Ukraini" - or Glory to Ukraine.
The Netherlands has been a strong supporter of Ukraine, with Rutte in February saying he did not rule out any kind of military support for Kyiv as long as it did not bring NATO into conflict with Russia.
Russia has stepped up attacks as Ukraine prepares for a counteroffensive to try to retake Russian-occupied land in the south and east. Russian shelling in the frontline southern region of Kherson killed at least 23 civilians on Wednesday.
(Reporting by Bart Meijer, Stephanie Van Den Berg, Toby Sterling; Writing by Ingrid Melander; Editing by Nick Macfie)