Ukraine has accused Russia of war crimes in the village of Bucha, close outside Kyiv, while Germany, France, and other countries have expressed anger at photographs of dead people.

On Saturday, the mayor of Bucha announced that 300 civilians had been slain by Russian forces during a month-long occupation. Reuters witnessed victims being buried in mass graves and laying on the streets.

The Russian military ministry disputed the Ukrainian charges, calling the film and images of bodies in Bucha “yet another provocation” by the Ukrainian government. Russia has repeatedly denied targeting people and rejecting charges of war crimes in Ukraine during what it refers to as a “special military operation.”

Even before Bucha, Ukraine and its Western allies accused Russian forces of indiscriminately hitting people, citing the bombardment of a maternity facility and a theatre labelled as a sanctuary for children in the southern port of Mariupol.

According to legal experts, prosecuting President Vladimir Putin or other Russian authorities would encounter significant obstacles and may take years, as described below:

HOW IS A WAR CRIME DEFINED?

The International Criminal Court in The Hague defines war crimes as “grave violations” of the post-World War II Geneva Conventions, which set out the international humanitarian rules that must be obeyed during times of war. Legal experts noted such breaches include purposely targeting people and striking lawful military targets when civilian losses would be “extreme.”

In 1954, the Soviet Union ratified the Geneva Convention. Russia revoked its recognition of one of the protocols in 2019, but it remains a signatory to the remaining agreements.

HOW MIGHT A CASE PROCEED?

Karim Khan, the International Criminal Court’s head prosecutor, said last month that he had launched an inquiry into alleged war crimes in Ukraine.

Russia and Ukraine are neither members of the ICC, and Moscow does not recognise the tribunal. However, Ukraine has agreed to investigate alleged crimes on its territory dating back to Russia’s takeover of Crimea in 2014.

Russia may opt not to cooperate with the ICC, in which case any trial would be postponed until a defendant is apprehended.