An explosion apparently occurred near the last known position of an Argentine submarine, the navy confirmed on Thursday, dashing last hopes of finding the vessel and its 44 crew members.
He said seven ships are mapping the bottom of the ocean where the submarine might be found and that weather conditions are expected to worsen Sunday.
"Until we have concrete evidence of where the submarine is, we can not conclude with a decisive affirmation", navy spokesman Capt. Enrique Balbi said.
The ARA San Juan search location straddles the edge of the continental shelf, where ocean depths vary, but reach as deep as 3,000 metres.
The agonising wait for news of the whereabouts of the ARA San Juan has intensified in recent days as fears grow that the oxygen supply on board could be running low.
The news was sorely received by relatives of the San Juan crew members.
However, Balbi said that "the malfunction could not be associated to the disappearance".
Its fate remains a mystery, but here's a look at what experts say may have caused the explosion.
The ARA San Juan hasn't been heard from since November 15, when it was travelling from the extreme southern port of Ushuaia to the coastal city of Mar del Plata.
The vessel's captain had radioed in a "failure" in the sub's battery system as well as a "short circuit" shortly before it disappeared, Argentine navy spokesman Gabriel Galeazzi said Monday, according to CNN.
The navy did not have enough information to say what the cause of the explosion could have been or whether the ARA San Juan could have been attacked, Balbi told reporters.
But family members said authorities were concealing the reality of what happened.
On Thursday it also emerged that an worldwide nuclear test-ban body that runs a global network of listening posts created to check for secret atomic blasts detected an "unusual signal" last week, close to where the submarine went missing.
Enrique Balbi, spokesman for the Argentine Navy (ARA), speaks during a press conference about Argentine's missing submarine ARA San Juan, in Buenos Aires, Argentina, on November 23, 2017.
Balbi said that the news of the abnormal sound was consistent with a separate report received Wednesday of an "acoustic anomaly" in the same area and around the same time. The organization is set up to monitor compliance with the proposed nuclear test ban treaty and has 11 hydroacoustic stations positioned around the world listening for signs of nuclear explosions. "Until now, there is no certainty or evidence, the search will continue".
Balbi said teams have been searching for the missing submarine in waters of the San Jorge Gulf, about 430 kilometers (268 miles) from the coast.