Argentina's Navy detected seven brief satellite calls Saturday that may have come from a submarine with 44 crew members that hadn't been heard from in three days. The communications "indicate that the crew is trying to re-establish contact, so we are working to locate the source of the emissions," the Navy said via Twitter; the calls lasted between four and 36 seconds. It has not been confirmed the calls came from the submarine, the ARA San Juan, though the AP reports that is the working hypothesis. Earlier Saturday, Navy rep Enrique Balbi said the area being searched off the country's southern Atlantic coast has been doubled as concerns about the fate of the submarine and its crew grew. "We are not discounting any hypothesis," Balbi said, adding that possibilities to explain the submarine's disappearance include "a problem with communications" or with its power system.
Authorities last had contact with the German-built, diesel-electric sub on Wednesday as it was on a voyage from the extreme southern port of Ushuaia to Mar del Plata. Argentine President Mauricio Macri said in a tweet that the country will use "all resources national and international that are necessary to find the submarine." Pledges of help came from Chile, Uruguay, Peru, and Brazil, as well as the United States, which sent a NASA scientific aircraft and a Navy plane. Britain was sending a polar exploration vessel, the HMS Protector, which British officials said should arrive Sunday. The US Navy ordered its Undersea Rescue Command based in San Diego, Calif., to deploy to Argentina to support the search. "We feel anguish. We are reserved but will not lose our hope that they will return," Marcela Moyano, wife of machinist Hernan Rodriguez, told television network TN.