North Korea has accused the US of engaging in a "hostile military act" and posing a "grave security threat" to the country by sending a nuclear submarine to a South Korean port. The USS Alexandria entered the Busan port on Monday for supplies and rest for its crew,

A US Navy submarine docked at a naval base in South Korea on Monday, purportedly to replenish supplies—drawing a strong reaction from North Korea, which labeled the act an "undeniable threat." "We express grave concern over the US dangerous hostile military act,