US nuclear-powered submarine arrives in South Korea for first time in six years

A US nuclear-powered guided missile submarine (SSGN) arrived in South Korea on June 16 for the first time in six years, Seoul's defence ministry said, amid heightened tensions after North Korea's launch of two ballistic missiles the previous day.

The Ohio-class SSGN, USS Michigan, entered a key naval base in Busan, 320 kilometres southeast of Seoul, after North Korea fired two short-range ballistic missiles toward the East Sea on June 15 in an apparent protest against the allies' massive live-fire drills that ended earlier in the day, Yonhap  News Agency reports.

It marks the first time the US has sent an SSGN to South Korea since October 2017. The submarine is scheduled to stay in the country until June 23, a South Korean defence official told reporters on condition of anonymity.

The arrival of the submarine, a key asset of the US Navy, also came after the United States pledged to further enhance the "regular visibility" of strategic assets on the Korean Peninsula through the Washington Declaration issued by President Yoon Suk Yeol and US President Joe Biden during their summit in Washington in April.

"The US. SSGN's visit to South Korea is intended to substantively implement the agreement in the Washington Declaration made in April to enhance the regular visibility of strategic assets on the Korean Peninsula," ROK (Republic of Korea) Fleet Commander Vice Adm. Kim Myung-soo was quoted as saying.

"[It] demonstrates the overwhelming capabilities and posture of the South Korea-US alliance to realize 'peace through strength'," he added.

During the submarine's visit to the country, the South Korean and US navies plan to conduct combined special operations drills to strengthen their interoperability and capabilities in such operations as responding to advancing North Korean threats, according to the ministry.

The SSGN will also take part in various friendly exchange activities with the South Korean Navy to mark the 70th anniversary of the two countries' alliance.

Commissioned in 1982 as a nuclear-powered ballistic missile submarine, the USS Michigan was converted into an SSGN in 2007. The submarine is able to conduct strike missions using Tomahawk cruise missiles.

The 18,000-ton SSGN is 170 metres long and can be armed with over 150 Tomahawk missiles, which have a range of 2,500 kilometres, according to the ministry.

On June 15, the allies ended the fifth and last round of the Combined Joint Live-Fire Exercise, the first of its kind in six years, at a training field near the inter-Korean border to mark the alliance's landmark anniversary.

As part of the Washington Declaration, the US has also pledged to send a nuclear ballistic missile submarine to the country for a visit.