US and South Korean troops have begun major annual land, sea and air exercises, The Key Resolve / Foal Eagle drills, amidst North Korean threats.

The Key Resolve / Foal Eagle drills will be defensive in nature, while training the forces to respond to any provocation.

The drills involve 12,300 US troops and 200,000 South Korean service members, including reservists, according to Agence France Presse.

The 11-day Key Resolve drill focuses on computer-based simulations, while the Foal Eagle exercise involves field training.

The annual exercises are the first to be held since the North’s deadly artillery attack on a South Korean border island in November.