While adding to its barrage of missile launches in recent months, North Korea remained publicly silent for a fifth day on the fate of an American soldier who bolted into the North across the heavily armed Korean border this week.

South Korea's Joint Chiefs of Staff said the launches were detected beginning around 4 am but did not immediately report how many missiles were fired or how far they flew. It said the US and South Korean militaries were closely analysing the launches.

On Wednesday, North Korea fired two short-range ballistic missiles from an area near its capital, Pyongyang. They flew about 550 kilometers (341 miles) before landing in waters east of the Korean Peninsula.

The flight distance of those missiles roughly matched the distance between Pyongyang and the South Korean port city of Busan, where the USS Kentucky on Tuesday made the first visit by a US nuclear-armed submarine to South Korea since the 1980s.

The United States and South Korea have been expanding their combined military exercises and have agreed to increase the regional deployment of US strategic assets like bombers, aircraft carriers and submarines in a show of force against North Korea, which has test fired around 100 missiles since the start of 2022.

The allies have also kicked off new rounds of nuclear contingency planning meetings that are partially aimed at easing fears among the South Korean public about the North's growing nuclear threat and suppressing voices within the country that it should pursue its own deterrent.

North Korea's defense minister issued a veiled threat Thursday suggesting the docking of the Kentucky in South Korea could be grounds for a nuclear attack by the North. North Korea has used such rhetoric before, but the comments underscored how much relations are strained now.

South Korea's Defence Ministry on Friday described the deployment of the Kentucky and the nuclear contingency planning meetings between Washington and Seoul as “defensive response measures” to counter the North Korean threat. The ministry said in a statement it “strongly warns” that any nuclear attack by the North on the allies would face an “immediate, overwhelming and decisive response … that would bring an end to the North Korean regime.”?