The report, jointly compiled by the US Department of Homeland Security (DHS) and the Federal Bureau of Investigation (FBI), names Fancy Bears' amid a list of 48 "alternate names" for "Reported Russian Military and Civilian Intelligence Services".

Similar links have been drawn by other security services ever since Fancy Bears' first published dozens of confidential athlete information obtained following hacks of the World Anti-Doping Agency (WADA) in September.

But this marks the first time they have been directly implicated by a US Government body.

“The activity by [Russian intelligence services] is part of an ongoing campaign of cyber-enabled operations directed at the US Government and its citizens,” the 13-page report concludes. 

“This [joint analysis report] provides technical indicators related to many of these operations, recommended mitigations, suggested actions to take in response to the indicators provided, and information on how to report such incidents to the US Government.”

The report was published as outgoing US President Barack Obama announced that 35 Russian diplomats would be expelled from the country in response to alleged intervention in last month's Presidential election in which Republican Donald Trump defeated Obama's fellow Democrat, Hillary Clinton.

It had been expected that 35 US diplomats would also be forced to leave Russia in a tit-for-tat response, but the country's President Vladimir Putin has now announced that they will not stoop to "irresponsible diplomacy" and do this.

Russian groups have also been blamed for other hacking incidents including a 2008 attack on the Georgian elections and an infiltration of the French news channel, Le Monde in 2015.

Sport and the Olympic Movement, despite its claims to be politically neutral, has been dragged firmly into this game of power politics.

Fancy Bears' released the first raft of six leaks of confidential information relating to athletes predominantly from North America and Western Europe.

Most related to legally-obtained Thereputic Use Exemptions (TUE) in which athletes had obtained permission to take otherwise banned substances for medical reasons.

Leading athletes including leading US stars such as tennis legend Serena Williams and four-time Rio 2016 gold medal winning gymnast, Simone Biles, as well as two British Tour de France winning cyclists in Sir Bradley Wiggins and Chris Froome are among the names published on the Fancy Bears' website.

There is no suggestion of any of the athletes named having done anything illegal and, despite huge criticism in Russia, the TUE system has been defended by both WADA and the International Olympic Committee.

The Fancy Bears' attacks, which have since been followed by more leaked documents from WADA and other bodies such as the United States Anti-Doping Agency, have been interpreted as an attempt to avenge the investigations into Russian doping at the Sochi 2014 Winter Olympic and Paralympic Games and other major sporting events.

According to the WADA-commissioned McLaren Report, around 1,000 Russian athletes have had their samples illegally manipulated and tampered with in a state-sponsored scheme.

Russia was duly suspended and barred from competing in Rio by the International Paralympic Committee, International Association of Athletics Federations and International Weightlifting Federation.

Russian figures from Putin downwards continue to deny wrongdoing.

They also deny any link with Fancy Bears' and other hacking groups.

The US Government report can be read in full here