North and South Korea are locked in a dangerous arms race. Putin may be about to make this worse.

• North Korea and South Korea are in an intensifying arms race. 
• North Korea has launched a series of missile tests. 
• Russia's new alliance with North Korea could worsen the situation. 

North Korea on Monday claimed it had tested a new weapon capable of far greater destruction than the ballistic missiles in its arsenal.

The Hwasong-11Da-4.5, which has a 4.5-ton warhead, follows South Korea's development of multi-ton warhead ballistic missiles, designed as "bunker busters" that can take out North Korean nuclear bases, amid an intensifying arms race on the peninsula.