pact

The Koreas have also suspended a pact aimed at lowering military tensions between them, shortly after North Korea said that the South was now “enemy number one”.

But throughout the war, both sides have taken care to avoid turning the conflict into a direct battle between Russia and NATO, whose 32 member nations, including the United States, have a mutual-defense pact.

But there is no doubt that the pair have stepped up cooperation after signing a security pact in June to help each other in the event of "aggression" against either country.

The UK already has a defence pact with France – the Lancaster House Treaty which was signed in 2010 by David Cameron and Nicholas Sarkozy – but this is the first with Germany.

Last week, Putin introduced a bill to ratify the pact.