The eight rules, including a ban on attacking hospitals, a ban on threatening civilians, and the production of computer viruses that spread uncontrollably.

ICRC legal adviser Dr Tilman Rodenhäuser said that some experts consider civilian hacking activity as 'cyber-vigilantism' and argue that their operations are technically not sophisticated and unlikely to cause significant effects. However, some groups we're seeing on both sides are large, and these 'armies' have disrupted banks, companies, pharmacies, hospitals, railway networks and civilian government services.

The BBC highlights the IT Army of Ukraine, which has 160,000 members on its Telegram channel and has targeted Russian civilian infrastructure, among other targets. It told BBC News it hadn't decided whether to implement the rules, emphasised it did not attack medical targets, and added: "Adhering to the rules can place one party at a disadvantage."

The Russian cyber group Killnet's leader, Killmilk, responded even more starkly: "Why should I listen to the Red Cross?"