Ukraine has filed a suit against Russia at the highest UN court in The Hague for disputes between states, President Volodymyr Zelensky said on Sunday.
It was unclear on precisely what grounds the case was being brought to the International Court of Justice (ICJ).
"Ukraine has submitted its application against Russia to the ICJ," Zelensky said on Twitter.
"Russia must be held accountable for manipulating the notion of genocide to justify aggression. We request an urgent decision ordering Russia to cease military activity now."
The court does not have automatic jurisdiction in cases involving the two nations and Kyiv would have to base its claim on a UN treaty in order to give the court authority to hear the matter.
Ukraine has in the past sought to involve another court in The Hague, the International Criminal Court (ICC), which handles war crimes.
Following the Russian annexation of Crimea in March 2014 and subsequent fighting in eastern Ukraine between pro-Russian rebels and Ukrainian government forces, Kyiv accepted ICC jurisdiction for crimes against humanity and war crimes committed on its territory since February 2014.
In December 2020, the office of the prosecutor announced it had reason to believe war crimes and other crimes were committed during the conflict.
A formal request to open a full investigation has not been filed with judges, but ICC prosecutor Karim Khan on Friday expressed his concern over the Russian invasion and said the court may investigate alleged crimes arising from the current situation.