The officials stressed an evacuation remains an extremely remote possibility and the Obama administration is not currently planning for one. Americans who wish to leave the region now are able to do so using commercial airlines.
But the decision to send the ships even if the event is such a remote contingency underscores the growing concern about where the Israel-Gaza conflict could be headed.
"This is due diligence. It is better to be prepared should there be a need," one official said Monday. Both officials said the ships would be used only for assisting Americans and not for any combat role.
The most immediate impact will be on the ships' crews and the estimated 2,500 Marines on board. They had been scheduled to return to Norfolk, Virginia, just after Thanksgiving; their homecoming will now be delayed several days depending on events, the officials said.
The ships involved are the USS Iwo Jima, the USS New York and the USS Gunston Hall. At the end of last week the ships were west of Gibraltar, before the decision was made to turn them around and send them back to the eastern Mediterranean, where they will remain for now.
The U.S. military also maintains three to four ships off the coast of Israel that are capable of shooting down ballistic missiles. That deployment has stretch for some months in the face of a potential ballistic threat from Iran.