This was stated by British Prime Minister David Cameron in a letter to NATO leaders ahead of the Wales summit, Censor.Net informs, referring to Liga.NET.
He said that Russia has "ripped up the rulebook with its illegal annexation of Crimea". Cameron also reiterated previous accusations against Moscow in the illegal arms supply to the separatists in eastern Ukraine.
See also: Map of the ATO Area: Terrorist Controlled Territory Can Be Cut in Three Parts - Ukrainian Army Continues to Tighten the Ring. PHOTO
Russia actions after Malaysian Boeing crash were also criticized by Cameron.
We must agree on long-term measures to deter any Russian aggression and to reassure those allies who fear for their own country's security, Cameron concluded.