The Royal Navy has deployed its elite submarine rescue team to join the search for a missing Argentine submarine, after failed satellite calls thought to be from the vessel raised hopes the crew were still alive.
HMS Protector also began scouring the South Atlantic as part of the international hunt for the missing vessel, and HMS Clyde was being diverted from South Georgia.
Argentine officials said naval bases had detected seven incomplete satellite calls over the weekend attributed to the sub and were now trying to use them to pinpoint its location.
The communication attempts "indicate that the crew is trying to re-establish contact, so we are working to locate the source of the emissions," the Argentine Navy said on its Twitter account, adding that the calls lasted between four and 36 seconds.
An international team of ships and aircraft were braving heavy seas and high winds to search for the German-built ARA San Juan which has been lost since last week.
The Royal Navy said it was flying the Submarine Parachute Assistance Group (SPAG) to the region to join the hunt. The highly trained team of medics, engineers and escape specialists is continuously on six hours notice to go anywhere in the world.
Team members are parachute trained so that they can leap into the water at the scene if needed, but in this case will embark on HMS Protector. They carry inflatable boats and life rafts, medical equipment and communications gear which allows them to talk to trapped crews.
Arrived on task in the search area in the early hours of this morning and have commenced sonar and visual search for #ARASanJuan as part of the ongoing multinational operation. Conditions remain challenging given current weather. pic.twitter.com/Sxgi9MZGo5— HMS_Protector (@protector_hms) November 19, 2017
The San Juan and its 44 crew last made contact on Wednesday when she was 267 miles off the coast in the Gulf of San Jorge.
The latest possible calls were a sign for “cautious enthusiasm”, naval experts said, showing the crew may be alive, afloat and at a shallow enough depth to attempt to communicate.
Claudio Rodriguez, whose brother Hernan is aboard the submarine, told a local television channel: "They've got to be afloat. Thank God. That gives us hope, because we knew that if they were down below, they would be screwed.”
HMS Protector, the Royal Navy’s 5,000 ton ice patrol and survey ship, was diverted to join the search from a routine mission in the area and can bring its high definition sonar to bear on the search.
Search and rescue mission for Argentinian submarine
The hunt also includes help from Brazil, Chile, Uruguay and the United States. America on Sunday said it was sending a second P-8 Poseidon submarine hunting navy patrol plane to join the search. The US Navy has also dispatched two submarine rescue chambers that can dock onto stricken boats and ferry crew to the surface from hundreds of feet underwater.
The San Juan is a TR-1700 class submarine which had been returning from a routine mission to Ushuaia, near the southernmost tip of South America, to its base at Mar del Plata, about 250 miles south of Buenos Aires.
Timeline | Submarine accidents
Among those on board is Argentina's first female submarine officer, 35-year-old weapons officer Eliana Krawczyk.
Rescuers are focusing on an ocean patch about 190 miles in diameter located about 270 miles from the coast of the southern province of Chubut.