Think tank warns old enemies are increasing tensions with large-scale military exercises
Military jets are increasingly being called to 'maintain airspace integrity' resulting in tense mid-air interactions
The alliance 'stands in solidarity with its ally', but plays down speculation that it could provide military support
Samantha Power urges Europe to increase military spending and provide more peacekeepers
Defence secretary warns that Russia poses a 'real and present danger' to the Baltic States
'Hugely embarrassing' request for help made to US and France because of cuts to the defence budget
Incursion could violate the peace treaty as Ukrainian troops prepare for combat operations in the east
In ten days' time, Scotland could vote for independence. Here's what would happen after that momentous decision
Cameron and Obama have a lot of persuading to do as the West faces IS and Ukraine crises
Nato leaders will discuss Ukraine and the rise of the Islamic State – but what will the summit achieve?
Russia says it will review its own military doctrine in response to the 'growing Nato threat' in Europe
The Ukrainian government says its forces are now fighting Russian troops, not Russian-backed separatists
Putin and Poroshenko agree to work together, but Russia says it's up to Kiev to end the fighting
UK defence watchdog says major overhaul is required to defend against cyber-warfare and 'irregular militias'
Illuminati, a hit on Putin, Israeli foul play – just some of the theories that have emerged online
Typhoon fighter jets sent to investigate Russian long-range bombers approaching UK airspace
A quarter of a century after the Cold War, dreams of harmony and consensus are shot to pieces
Gun and bomb assault on president's Kabul palace is 'audacious', but does it mean Taliban are divided?
If we've decided to 'cut and run' by holding talks with Afghan insurgents, why not just cut and run now?