The US has charged two Russian spies with the biggest cyber attack ever carried out. The Department of Justice said that two "state-sponsored" Russian hackers were responsible for breaking into Yahoo and stealing 500 million accounts. The case would be the first ever brought against Russian officials. The charge comes amid increasing tensions between Russia and the US over the use cyber weapons and hacking. Multiple US intelligence agencies have accused Russian state-sponsored hackers of running a co-ordinated campaign to upset the result of the US election and increase the chances that Donald Trump would become president.