The prosecutor of the International Criminal Court (ICC) said on Tuesday she would investigate both sides in a 2008 war between Russia and Georgia for crimes including the killing of peacekeepers and attacks on civilians.
The prosecution office said Fatou Bensouda had been prompted to ask judges for permission to open the investigation after signs that Georgia's inquiries into its own forces' alleged crimes had stalled.
Some investigations are underway in Russia, her office said, meaning that the ICC, which is a court of last resort, might not have full jurisdiction over crimes covered by those probes.
Prosecutors said there was evidence that up to 113 ethnic Georgian civilians had been killed and up to 18,500 uprooted from their homes as part of a "forcible displacement campaign" conducted by the authorities in South Ossetia, a mainly Russian-speaking province.
"The Prosecutor estimates that the ethnic Georgian population in the conflict zone was reduced by at least 75 percent," they said, adding that the crimes had been committed with "the possible participation of the Russian armed forces".
The prosecutors said there was also evidence that Georgian and South Ossetian forces had both attacked peacekeepers. It said shells from South Ossetian positions had killed two Georgian peacekeepers while Georgian forces had killed 10 Russian peacekeepers and destroyed a medical facility.
Judges must now decide whether to authorise a full probe, which would pit Russia, which is not an ICC member, against the permanent European-backed global war crimes court at a time when east-west tensions are at their highest since the Cold War.
The Hague-based ICC is already considering whether to open an investigation into crimes committed in Ukraine, another West-leaning former Soviet republic which is fighting Moscow-backed separatists in the east of the country.
The ICC announcement came hours after Dutch authorities released their final report on the downing of Malaysia Airlines Flight 17 over eastern Ukraine in July 2014. The report concluded that a Russian-made Buk missile caused the crash, which killed all 298 people on board.