Workers used sonar equipment Monday to get the facts on an object found 26 days after an Argentine sub went missing with 44 crew members aboard.
President Mauricio Macri and the navy consider the crew to have been tragically lost.
But family members desperate for closure have been pushing for the search to continue until the vessel is located and questions about its fate are answered, despite a series of false hopes.
"A new object has been found at 1,000 meters (3,280 feet) with sonar search equipment in the South Atlantic. And it is being looked at to determine if it could be the Argentine sub," navy spokesman Enrique Balbi told reporters.
It was spotted by the US vessel Atlantis.
Authorities have not set any date for when the search might be officially abandoned.
The navy's final contact with the German-built ARA San Juan, a 34-year-old diesel-electric sub, came on November 15, when it was sailing in the South Atlantic 450 kilometers (280 miles) from the coast.
In its final communication, the submarine reported it had overcome a mechanical breakdown that resulted from a short circuit due to water that seeped through the vessel's snorkel.
Three hours later, a noise similar to an explosion was recorded 48 kilometers from where the crew had given its last report.
The position was in line with the planned path the submarine would have taken to reach its base in Mar del Plata, according to the navy.