Russia has denied sending soldiers or military equipment to eastern Ukraine and will challenge the basis of the case Ukraine has launched at the International Court of Justice in The Hague.
Ukraine urged the United Nations's top court on Monday to help bring stability to its war-torn east and order Russia to stop funding and equipping pro-Russian separatists.
The International Court of Justice is holding four-day hearings in a case brought against Russian by Ukraine, arguing Moscow is violating the Terrorism Financing Convention.
"Today I stand before the court to ask for the protection of the basic human rights of the Ukrainian people," Kiev's deputy foreign minister Olena Zerkal told the court in The Hague.
"Thousands of innocent Ukrainians have already suffered deadly attacks," she said.
Russia's deputies did not comment after the three-hour hearing, but a large delegation is present in The Hague.
Nearly three years of conflict have claimed about 10,000 lives in eastern Ukraine -- and led to Russia's seizure of Ukraine's southern peninsula of Crimea in 2014 -- pushing ties between Moscow and the West to their lowest point since the Cold War.
Kiev seeking emergency measures
Ukraine is asking the ICJ to impose emergency measures ordering Russia to stop its alleged funnelling of money, weapons and personnel into the east, and to halt what it called "discrimination" against minorities in Russian-occupied Crimea.
Ukraine "respectfully requests the court to adjudge and declare that the Russian Federation bears international responsibility by virtue of its sponsorship of terrorism... for the acts of terrorism committed by its proxies in Ukraine," it said in papers before the court.
Moscow also "brazenly defied" the UN Charter by seizing Ukraine's southern peninsula of Crimea, Kiev said in its filing, accusing Russia of discriminating against Crimean minorities such as Tatars and ethnic Ukrainians.
The ICJ was set up in 1945 to rule in disputes between countries.
The court takes years to hear cases. Although its rulings are final and binding, it has no means of enforcement.