Police in France say they now think the cyber attack on TV5 Monde in April was the work of a group of Russian hackers known as APT28, and not the group calling itself Islamic State, as originally suggested.

Jihadist propaganda was posted on TV5’s website during the infiltration in April. Details of serving French troops and their relatives were also published.

The station was forced to broadcast pre-recorded programmes after its screens went blank for several hours.

Reports in the French media claim APT28 has targeted high-profile sites in the past – including the White House and members of NATO.