The chief of the European Union's executive body has unveiled a plan to create an international institution to coordinate collecting evidence to prosecute Russia's crimes of aggression in Ukraine.

European Commission President Ursula von der Leyen met Ukrainian President Volodymyr Zelenskyy in Ukraine's capital Kyiv on Thursday.

Von der Leyen told a news conference after the meeting that "an International Centre for the Prosecution of the Crime of Aggression in Ukraine will be set up in The Hague."

She said that Russia must be held legally accountable for "its odious crimes."

Von der Leyen said Europe "has been by Ukraine's side since day one" of Russia's invasion, and called the conflict "a fight of democracies against authoritarian regimes."

She added, "Our presence in Kyiv today gives a very clear signal: The whole of the European Union is in this with Ukraine, for the long haul."

The EU agreed on 500 million euros, or about 540 million dollars, in additional military aid for Ukraine last week.

Von der Leyen also said that by the first anniversary of the invasion on February 24, "we aim to have the tenth package of sanctions in place."

Zelenskyy noted that the pace of sanctions by European nations "has slowed down a bit."

He urged European countries "to reduce Russia's ability to circumvent sanctions." He said, "The faster and better this task is accomplished, the closer we will be to defeating the aggression" by Russia.