Russia is worried about North Korean missile and nuclear tests and has deployed sophisticated air defences in its Far East region to protect against any potential test mishap,Russias top general said here on Wednesday. We have an S-400 division there, said General Nikolai Makarov,chief of staff of the Russian armed forces,confirming that Russia had deployed its most advanced anti-missile defence system near the border with North Korea.Russia is worried about North Korean missile and nuclear tests and has deployed sophisticated air defences in its Far East region to protect against any potential test mishap,Russias top general said here on Wednesday. We have an S-400 division there, said General Nikolai Makarov,chief of staff of the Russian armed forces,confirming that Russia had deployed its most advanced anti-missile defence system near the border with North Korea.