The United States is considering shooting down any North Korean ballistic missiles, even if they are not a threat to the U.S., Japan or South Korea, CNN reported early Tuesday morning.

Also, on Tuesday, combined military forces from the United States and South Korea conducted an arms training exercise in Pocheon amid heightened tension in the wake of North Korea's increasingly frequent missile and nuclear tests.

About 700 troops are engaged in the four-day drill, called Warrior Strike 8, near the Demilitarized Zone (DMZ) - the world's most heavily defended frontier. The U.S. military has described the exercises as training for readiness "to fight tonight" against North Korea if needed.

The drill was conducted after Pyongyang fired another mid-range ballistic missile over Japan on Friday (September 15) only four days after the U.N. Security Council unanimously stepped up mandating tougher sanctions against Pyongyang.

South Korea and the United States are technically still at war with North Korea after the 1950-53Korean conflict ended with a truce, not a peace treaty. North Korea has repeatedly demanded that they call off joint exercises, which Pyongyang views as provocative.