Major military exercises begin between Washington and Seoul

South Korea and the United States on Monday began their biggest joint military exercises in five years, despite threats from North Korea, which announced hours earlier that it had fired two cruise missiles from a submarine.

Pyongyang said the missile launches were intended to test "nuclear deterrence in different spaces," while criticizing Freedom Shield exercises between U.S. and South Korean forces, scheduled to last ten days to combat growing threats from Pyongyang.

South Korea's military said the drills "include wartime exercises to repel potential North Korean attacks and conduct a stabilization campaign in the North."

South Korea's Joint Chiefs of Staff stressed that the drills were "defensive and based on a joint operations plan."

Such exercises infuriate Pyongyang, which sees them as a simulation of an invasion of its territory, and regularly threatens "crushing" action in response.