The location of a U.S. submarine that can launch nuclear missiles has been announced by the Pentagon in a rare move as the Iran war drags on .

Usually, the Pentagon is tight-lipped about the locations of its nuclear-armed submarines. But on Monday, the Sixth Fleet announced that a Navy ballistic missile submarine arrived in Gibraltar, a British territory off the coast of Spain , on Sunday.

The Sixth Fleet is part of the U.S. Naval Forces Europe and Africa, which covers about half of the Atlantic Ocean.

In a statement announcing the submarine’s port visit, the Sixth Fleet said the vessel is part of the Ohio-class ballistic missile submarines. The Ohio-class is comprised of 14 ballistic missile submarines and four guided missile submarines.

Those 14 submarines “are undetectable launch platforms for submarine-launched ballistic missiles, providing the U.S. with its most survivable leg of the nuclear triad,” the release stated.

The location of a U.S.…