Judges at the European Court of Human Rights on Wednesday delivered decisions on four cases brought by Ukraine and the Netherlands against Russia since the start of the conflict in 2014.
The allegations include murder, torture, rape, destroying civilian infrastructure, kidnapping Ukrainian children and shooting down the Malaysian Airlines passenger jet, Flight MH17, by Ukrainian separatists who side with Russia.
Reading the decisions before a packed courtroom in Strasbourg, Court President Mattias Guyomar said Russian forces breached international humanitarian law in Ukraine by carrying out attacks that "killed and wounded thousands of civilians and created fear and terror".
The judges found the human rights abuses went beyond any military objective and Russia used sexual violence as part of a strategy to break Ukrainian morale, the French judge said.
"The use of rape as a weapon of war was an act of extreme atrocity that amounted to torture," Guyomar said.
The complaints were brought before the court's governing body expelled Moscow in 2022, following the full-scale invasion.
The decisions are largely symbolic since Moscow says it plans to ignore them.
"We won't abide by it, we consider it void," Kremlin spokesperson Dmitry Peskov said in a call with reporters.
Families of the victims of the MH17 disaster see the decision as an important milestone in their 11-year quest for justice.
"It's a real step in understanding who was really responsible," Thomas Schansman, who lost his 18-year-old son Quinn in the tragedy, told The Associated Press.
The Boeing 777 flying from Amsterdam to Kuala Lumpur was shot down on July 17, 2014, using a Russian-made Buk missile fired from territory in eastern Ukraine controlled by separatist rebels.
All 298 passengers and crew were killed, including 196 Dutch citizens and 38 Australians.
In May, the UN's aviation agency found Russia responsible for the disaster.
The ECHR is an important part of the Council of Europe, which is the continent's foremost human rights institution.
Russia was expelled from the council over Moscow's invasion and war in Ukraine.
However, the court can still deal with cases against Russia dating from before its expulsion.
In 2023, the judges sided with Ukraine and the Netherlands in a challenge over jurisdiction, finding there was sufficient evidence to show areas in eastern Ukraine controlled by separatist rebels were "under the jurisdiction of the Russian Federation", including providing weapons, and giving political and economic support.
Wednesday's rulings will not be the last from the EHCR dealing with the war.
Kyiv has other cases pending against Russia and there are nearly 10,000 cases brought by individuals against the Kremlin.
The decisions in Strasbourg are separate from a criminal prosecution in the Netherlands in which two Russians and a Ukrainian rebel were convicted in absentia of multiple murders for their roles in the downing of Flight MH17.
In 2022, the United Nations' top court ordered Russia to stop military operations in Ukraine while a case is heard, a process that takes years.
Russia has flouted the order by the International Court of Justice.
In June, Ukrainian President Volodymyr Zelenskiy formally approved plans to set up a new international court to prosecute senior Russian officials for the full-scale invasion of Ukraine.
