The 34-year-old submarine had gone through a refit and was "in ideal condition", Macri told reporters at the Argentine navy headquarters.
Argentine Navy officials embrace inside the Mar de Plata Naval Base after Argentina's Navy announced that a sound detected during the search for the missing ARA San Juan submarine is consistent with that of an explosion, in Mar de Plata, Argentina on November 23.
Reports of a sound detected underwater near the submarine's last known position off Argentina's southern coast in the Atlantic last week suggest it may have imploded at depth.
"We are at a stage of hope and hopelessness at the same time", Balbi told reporters.
But many relatives of the crew have lost hope since the navy announced Thursday that there had been an explosion on board the submarine, which experts said was likely linked to a problem with its batteries and would likely have been catastrophic.
Missing sub was in good condition: navy
"Two days before setting sail, there was a check of the whole operating system", navy spokesman Enrique Balbi said as a news conference on Saturday.
Some relatives of the crew have claimed the navy put their loved ones at risk in a vessel that is more than 30 years old.
Weather conditions for the search were good Saturday - better than the hard stormy weather of the past week - but likely to deteriorate on Sunday. "They are gone, but are not 'dead'".
Since then, there has been no contact with the San Juan, and no signs of the ship or debris despite an intensive search. A Russian plane arrived in Argentina on Friday carrying search equipment capable of reaching 6000m below the sea surface, Balbi said.
President Mauricio Macri has ordered an inquiry to "know the truth" about what happened to the San Juan. It joins HMS Protector, a Royal Navy ice patrol ship; the HMS Clyde, an offshore patrol vessel; and an RAF C-130 in the search.
London's Oxford Circus On Lockdown After Reports of Shots Fired
A Transport for London spokesperson said: " Oxford Circus is heavily restricted on all approaches to a police incident". London's Metropolitan Police said there was no evidence of shots fired or casualties at the Oxford Circus tube station.