A U.S. nuclear submarine armed with cruise missiles arrived in the South Korean port of Busan on Friday, the first such visit in almost six years amid allied efforts to bolster deterrence against North Korea.

The Ohio-class U.S.S. Michigan guided missile submarine (SSGN) will take part in exercises with the ROK navy to enhance special warfare capabilities and interoperability to counter DPRK nuclear threats, Seoul’s defense ministry said in a press release.

Armed with some 150 Tomahawk cruise missiles, the 18,000-ton submarine is one of the world’s largest and highlights the U.S. commitment to defend South Korea under the