North Korea Fires Latest Short-Range Missiles During US-South Korean Military Exercises

North Korea has launched a fresh military test-firing of short-range missiles into the Sea of Japan as it flexes its military muscles during joint US-South Korean military exercises.

South Korean news agency Yonhap reported the launch of two KN-O2 missiles, an upgraded version of SS-21 short-range missiles. They have a range of 74 miles.

"The launch was seen as testing its capability for short-range missiles. It seemed to be conducted on a military-unit level, not at a national level," said a military source in Seoul.

The report of the test-firing has not been confirmed by other sources.

The North Korean army has threatened "merciless retaliation" against South Korea and the US for their military exercises.

The UN and US imposed new sanctions as punishment for Pyongyang's nuclear test in February and the North responded to that by again threatening a pre-emptive nuclear strike against the United States. Defence experts believe it does not have the technical ability to do that.

North Korea has accused the US of using the military drills ias a rehearsal for war and has threatened to scrap the 1953 armistice that ended hostilities in the 1950-53 war in the peninsula. It has threatened to unleash a second Korean War, backed by nuclear weapons.