http://www.independent.ie/world-new...n-against-nuclear-sabrerattling-34181629.html The US defence secretary has issued his strongest warning yet about Russian aggression in Europe and the Middle East. He accused the Kremlin of "nuclear sabre-rattling" and said Vladimir Putin was "way off track" in Syria. Ash Carter said the US was adapting its "operational posture and contingency plans" after Russia's violation of the sovereignty of Ukraine, intimidation of Baltic states, and its intervention in Syria. He also expressed his "deep concern" about China's building of artificial islands in the South China Sea, saying it could lead to future military conflict between nations in the region. Mr Carter, who recently returned from an eight-day visit to Asia, was speaking at the Reagan National Defence Forum in California. He said: "At sea, in the air, in space and in cyberspace, Russian actors have engaged in challenging activities. "And, most disturbing, Moscow's nuclear sabre-rattling raises questions about Russian leaders' commitment to strategic stability, their respect for norms against the use of nuclear weapons and whether they respect the profound caution that nuclear-age leaders showed with regard to the brandishing of nuclear weapons. "We do not seek a cold, let alone a hot, war with Russia. We do not seek to make Russia an enemy." He continued: "But make no mistake, the United States will defend our interests, our allies, the principled international order, and the positive future that it affords us all." Mr Carter said that the US was investing in new weapons technology which was "relevant to Russia's provocations". These include an electromagnetic rail gun, lasers, new electronic warfare systems, and "a few surprising ones I really can't describe here".