Russia and the US send nuclear bombers to North Korea
A spokesman said: "Two strategic bombers Tupolev-95MS of Russia’s Aerospace Force have carried out routine flights over international waters of the Sea of Japan and the western part of the Pacific Ocean.
"At certain sections of the route the Tupolev-95MS crews were accompanied by a pair of F-18 fighters (of the US Air Force), and a pair of F-15, F-4 and F-2A fighters (of the Japanese Air Force)."
The threat of nuclear missile attack by North Korea is accelerating, US defence secretary Jim Mattis warned at the weekend.
Mattis made his remarks as he accused the North's leader Kim Jong-un of "illegal and unnecessary missile and nuclear programmes".
Speaking in Seoul alongside South Korean defence minister Song Young-moo, he warned: "North Korea has accelerated the threat that it poses to its neighbours and the world."
Because of this, he said, military collaboration between the US and South Korea had taken on "a new urgency".
Mattis added: "Any use of nuclear weapons by the North will be met with a massive military response."