Ohio-class ballistic-missile submarine USS West Virginia (SSBN-736) conducts a port visit at U.S. Navy Support Facility (NSF) Diego Garcia during a scheduled patrol.
CNN  — 

The US military wants its adversaries, as well as allies, to know that, for the first time, a US Navy nuclear-powered ballistic missile submarine docked at the remote island of Diego Garcia in the Indian Ocean as part of an extended months-long deployment.

This week, the Navy revealed the docking of the USS West Virginia and its port visit that actually took place from October 25 to 31. The specific movements of Navy submarines are highly classified while they are sea, so the delayed announcement would have given the submarine the time to transit to other locations in the Indian Ocean.

The significance of publicizing the port call of the USS West Virginia is to send a message to potential adversaries as well as allies, according to a military official familiar with the unusual port stop.

“They should take from this that a ballistic missile submarine which is undetectable can operate in any ocean for an extended period,” the official said.

Diego Garcia is a highly militarized island south of the equator that is used by both US and British forces. The remote location gave the nuclear-missile-equipped submarine the ability to switch out the 150-person crew unobserved by outsiders, therefore preserving the secrecy of the submarine’s operations and allowing the sub to remain in the region for a longer period of time.

Although the official declined to specify as to whether the message was aimed at China, Russia or North Korea, the underwater stealth of US submarines is critical to gathering highly classified signals intelligence about adversaries as well as providing the sea-based leg of the nuclear deterrent by carrying nuclear-tipped intercontinental ballistic missiles.

“Every operational plan rests on the assumption that nuclear deterrence is holding, and (ballistic missile submarines) like West Virginia are vital to a credible nuclear deterrence for the United States and our allies,” Adm. Charles Richard, commander of US Strategic Command, said in a statement.

A typical submarine patrol lasted 10 to 12 weeks, according to the official, and by switching out crew, a patrol can be extended by several weeks. The USS West Virginia is one of 14 Ohio-class submarines that carry a maximum of 20 ICBMs. They are specifically designed for extended patrolling, according to the Navy, with three large-diameter hatches that allow for rapid transfer of supplies and equipment.

Prior to the Diego Garcia port call, the West Virginia surfaced in the Arabian Sea so that Gen. Michael Kurilla, the commander of US Central Command, could come aboard and participate in a communications exercise “to validate emerging and innovative tactics in the Indian Ocean,” according to the Navy.