Why has North Korea fired a missile ahead of US-South Korea drills?

North Korea fired a ballistic missile toward the sea off the Korean Peninsula's east coast on Wednesday, according to South Korean and Japanese authorities. The launch originated from the North's Wonsan area.

The launch occurred just days ahead of major joint military exercises scheduled by Seoul and Washington. Pyongyang has repeatedly condemned these allied military drills, denouncing them as a rehearsal for an invasion.