Washington is competing with Moscow and Beijing to develop technology that travels at speeds similar to ballistic missiles but is more agile and tougher to shoot down

Leader Kim Jong Un personally oversees launch of 'glide vehicle' that hits target 1,000 kilometers away, says state media; US says firing violates 'multiple UN resolutions'

Milley is 1st Pentagon official to confirm nature of Beijing test of nuclear-capable hypersonic weapon that orbited Earth then reentered atmosphere

Financial Times says US intelligence officials reportedly caught by surprise by Beijing's progress on weapons; Pentagon: 'We hold China as our number one pacing challenge'

Pyongyang says test of new type of missile, which is harder for defense systems to intercept, was of 'great strategic significance'

Pentagon says hypersonic weapons needed 'to dominate future battlefields,' but critics warn they could fuel dangerous new arms race

Avangard hypersonic glide vehicle can travel 27 times the speed of sound and zig-zag through atmosphere en route to target, making it almost impossible to intercept