What is a war crime and could Putin be prosecuted over Ukraine?

US President Joe Biden has called Vladimir Putin a "war criminal" - when discussing the conflict in Ukraine.

Ukrainian President Volodymyr Zelensky and UK Prime Minister Boris Johnson have previously both accused Russia of carrying out war crimes.

What is a war crime?

It may not seem like it, but "even war has rules", as the International Committee of the Red Cross puts it.

These are contained in treaties called the Geneva Conventions and a string of other international laws and agreements.

Civilians cannot be deliberately attacked - nor can the infrastructure that...