Argentine submarine search no longer a rescue mission

After 15 days of a desperate rescue operation, the Argentine Navy has officially given up on finding the 44 crew members aboard the ARA San Juan submarine alive.

Navy spokesman Enrique Balbi confirmed a reorganisation of vessels and assets would take place with the mission changing from rescue to recovery.

Equipped with an oxygen supply for 7-10 days, Mr Balbi said the navy's rescue attempt "extended for more than twice what is estimated for a rescue".

On November 15, the San Juan went missing about 400 kilometres off the coast in the South Atlantic while patrolling between a base in Argentina's far southern Tierra del Fuego archipelago to its home in Mar del Plata in the north.

The final contact from the sub, reportedly indicated seawater had entered the ventilation system, causing a battery on the diesel-electric vessel to short-circuit and spark a fire.

Prior to that, the sub had already been ordered back to its naval base after the captain reported an electrical problem in a battery compartment.

Then on Tuesday, the navy said an explosion-like sound was detected in the ocean near San Juan's last known location on the day it disappeared.

More than a dozen countries including Argentina, the United States, Great Britain, Chile and Brazil joined the hunt with ships and aircraft, but storms and rough seas complicated efforts.

As Argentina mourns for the crew members, President Mauricio Macri has promised the grieving families and friends a full investigation to find out why the 34-year-old and recently refitted vessel disappeared.

"We should not venture into looking for people to blame," he told a news conference.

"This will require a serious, deep investigation that reveals certainties about why we are witnessing what happened. My commitment is with the truth."