Russian spies charged by US over Yahoo data hack

US Department of Justice officials have indicted four individuals over the massive data breach of Yahoo user accounts - two of which having been identified as Russian spies.

As many as 500m accounts were hacked in 2014, with Yahoo blaming the cyber attack on a "state-sponsored" entity.

"The Department of Justice is continuing to send a powerful message that we will not allow individuals, groups, nation states, or a combination of them to compromise the privacy of our citizens, the economic interests of our companies, or the security of our country," said acting assistant attorney general Mary McCord.

The two officers of the Russian Federal Security Service were named as Dmitry Dokuchaev and Igor Sushchin, and were arrested in recent weeks in relation to the case.

Yahoo has been the victim of multiple cyber attacks, with another major hack affecting more than one billion accounts associated with the internet company. It felt the financial impact of the security breaches after it was forced to accept a lower bid for the acquisition of its core internet business by US telecoms provider Verizon earlier this year.

The initial $4.8bn sale to Verizon was cut by $350m in February, with the company said to have been unhappy with not being informed earlier about the data breach.

"We are deeply grateful to the FBI for investigating these crimes and the DOJ for bringing charges against those responsible," Yahoo said in a statement on Wednesday.