President Joe Biden, Britain's prime minister and other world leaders say Russia and its president, Vladimir Putin, are guilty of war crimes in the continuing invasion of neighboring Ukraine. After photos and videos this month showed civilian bodies in a suburb of Kyiv named Bucha, Ukrainian President Volodymyr Zelensky called for an end to Russian "war crimes." Last week, his government said mass graves outside the port city of Mariupol are additional evidence of atrocities against civilians. The Organization for Security and Cooperation in Europe, based in the Austrian capital of Vienna, recently accused Russia of repeatedly targeting hospitals, schools, residential buildings, water facilities and a theater, leading to civilian deaths and injuries.

"War crimes" are violations of international laws governing the conduct of invasions and armed conflict. Four years after World War II's end, world diplomats approved a 1949 document called the Geneva Conventions that bans torture, genocide (mass murder), forced displacement, purposely killing and injuring non-combatants without military purpose, and extensively destroying non-military buildings.

The International Criminal Court, located in the Netherlands, has opened an investigation of events in Ukraine. Its top war crimes prosecutor went there to investigate. The besieged East European nation's top prosecutor says her office is working to document thousands of apparent war crimes by Russian commanders and soldiers. The court in The Hague, a Dutch city, tries people -- not countries -- and focuses on those with the most responsibility: leaders and officials. Inquiries take many years, and only a handful of convictions have ever been won.

Those found guilty of past war crimes include:

• Charles Taylor, president of Liberia, convicted in 2012 of crimes against humanity for atrocities in Sierra Leone (a neighboring country in Africa). Sentence: 50 years in prison.
• Radovan Karadži, leader of Bosnia, was found guilty of war crimes and crimes against humanity. Sentence: life in prison.
• Saddam Hussein of Iraq, convicted of crimes against humanity and executed in 2006.

President Biden says: "I called it genocide, because it’s become clearer and clearer that Putin is just trying to wipe out even the idea of being Ukrainian, and the evidence is mounting."

Journalist writes: "As long as a government remains in power, any war crimes charges against it, however well-proven, are likely be little more than symbolic. If those in power act as if they are immune to the laws of war, it is because, in practice, they often are." – Max Fisher, New York Times international affairs writer

U.S. diplomat says: "A report documents the catalogue of inhumanity perpetrated by Russia's forces in Ukraine. This includes evidence of direct targeting of civilians, attacks on medical facilities, rape, executions, looting, and forced deportation of civilians to Russia." – Michael Carpenter, American ambassador to the Organization for Security and Cooperation in Europe