The monster nuclear submarine the US sent to South Korea looks like it may be packed with Navy SEALs

The US Navy maintains that the USS Michigan, a submarine known for carrying special-ops teams, stopped in the South Korean city of Busan for a "routine port visit," but pictures of the event suggest a more clandestine purpose that may involve US Navy SEALs.

On top of the Michigan as it arrived in Busan appeared to be two silos for SEAL Delivery Vehicles, the tiny submarines used to transport US Navy SEALs and their equipment for their most covert missions deep in enemy territory.

The Navy confirmed to Business Insider that these pods are used by Naval Special Warfare units, but as a rule it does not disclose deployments of Navy SEALs.

In April, when the Michigan last visited Busan, South Korean media reported that it carried SEALs to train with South Korean forces for a "decapitation" mission, in which the US and South Korea would work together to kill North Korean leader Kim Jong Un and take out North Korea's nuclear command structure.

The US military, however, maintains it does not train for attempts at regime change, and it does not typically comment on SEAL deployments.

Now, as the US and North Korea trade nuclear threats and the US and South Korea gear up for another round of military drills, the Michigan has returned, sending a powerful message. The Michigan, a nuclear-powered submarine, used to carry nuclear missiles but now carries 150 Tomahawk precision-guided missiles.

The US operates only four such submarines, known as SSGNs, and rarely discusses their whereabouts.

In 2011 it was the USS Florida, a fellow SSGN, that kicked off US operations in Libya by launching more than 90 Tomahawks at targets there, beating down Libyan defenses before airpower and surface ships took control of the situation.

With not one but two SEAL Delivery Vehicle silos attached, the Michigan could deliver a considerable number of highly mobile SEALs to South Korea. Silos add drag and decrease the stealthiness of the Michigan, suggesting they were included for a reason.

Additionally, as the US continues efforts to put "maximum pressure" on North Korea, South Korea's Yonhap News Agency posted pictures of F-22 Raptor stealth jets training for an air show in South Korea.

Experts have told Business insider that the F-22 fits the profile of the type of weapon the US would use in the early salvos of fighting with North Korea.

On Sunday, Secretary of State Rex Tillerson said the US would continue diplomatic efforts with North Korea "until the first bomb drops," as President Donald Trump repeatedly hints at using force to solve the crisis.

Despite the outward appearance of war preparations, the Trump administration's aggressive approach to North Korea has yielded economic and diplomatic results. China has now gone further than ever before in sanctioning North Korea, and a handful of other important nations have also cut or reduced ties.

Trump is scheduled to visit South Korea in November.