The US reportedly already has a submarine near North Korea's shores, and an aircraft carrier will soon join it.
The US Navy's USS Michigan attack submarine arrived in Busan, South Korea's southern port city, on Friday, and it looks like it will be joined by a US aircraft carrier in a bold challenge to a defiant North Korea, Yonhap news reports.
The Michigan, a nuclear-powered attack submarine, carries with it some 150 Tomahawk cruise missiles that experts told Business Insider could prove incredibly useful in a strike on North Korea's nuclear infrastructure.
Additionally, the submarine is known to sometimes carry special forces. In April, South Korean media reported that Navy SEALs aboard the Michigan had trained with a local force to decapitate North Korea's Kim Jong Un regime.
The USS Ronald Reagan, the US's forward-deployed aircraft carrier based in Japan, also should head to South Korea in the coming days, according to Yonhap.
Additionally, the US Navy has reshuffled some Arleigh Berke-class destroyers to bolster missile defenses in the region.
South Korea news outlet Chosun reported recently that the US has been considering using this armada to test North Korea like never before, by sailing the aircraft carrier north of the Northern Limit Line, the de facto maritime border of North Korea.
When the US recently flew bombers over the Northern Limit Line, North Korea responded by saying it would shoot down US bombers even outside its airspace.
As a rule, the US Navy does not comment on future operations, but the Reagan has been spotted in Korea's vicinity recently.