The mysterious GRU, trained in 'non-linear warfare', is used by Vladimir Putin to destabilise nations with 12 officers charged with hacking Trump election in 2016
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The GRU, thought to be behind the Skripal Novichok poisoning, is one of the favourite organisations of Russian president Vladimir Putin.
The secret group trains its 25,000 soldiers in 'non-linear warfare' which can be used to destabilise nations through cyber attacks and espionage.
The GRU have been deployed in eastern Ukraine to support the separatist movement and are also thought to be behind alleged disruption ahead of the 2016 US presidential election.
Under Vladimir Putin Russia has stopped short of outright aggression but, through the GRU, have become masters of cyber warfare and underhand tactics.

What is the GRU?
The GRU is a combination of intelligence and special forces and is known in full as the Main Directorate of the General Staff of the Armed Forces.
It was started as an intelligence-gathering agency for the Bolshevik Red Army a century ago.
Ever since then it has remained separate from other intelligence organisations and was kept entirely separate from the more famous KGB during the Cold War but still ran operations during that time.
In 1985 Muslim extremists kidnapped four Soviet diplomats at the their Beirut embassy. The GRU were sent to resolve the situation.
Once they heard a hostage had died officers soon tracked down a hostage taker's family member and, according to reports, they "castrated them, cut him down into pieces and sent him to the hostage takers" before threatening to kill more.
The remaining three Russian hostages were freed.
What happened after the Cold War?
At the end of the Cold War in the early 1990s the KGB was "broken up with separate domestic and foreign intelligence services complete with new names," NPR national security correspondent Greg Myre said.
He added: "The lesser-known GRU, founded a century ago by Russian revolutionary Leon Trotsky, just kept going under the same name."
And now it is at the cutting edge of cyber espionage operations in the Russian Federation.