The Argentine Navy is investígating a new signal detected in the South Atlantic, which it believes may have come from the missing ARA San Juan submarine.
In a statement issued Saturday, the Navy said it would search the area the signal is believed to have come from with the help of the Russian submersible "Panther Plus" and U.S. oceanographic vessel "Atlantis."
At least 13 countries have offered to help in the search for the San Juan, which disappeared in November, but so far the effort has turned up no substantial results.
On November 15, the submarine was en route to the Mar del Plata naval base, 400 kilometres south of Buenos Aires, after departing a few days earlier from Ushuaia, at the southern tip of the American continent.
That day, an international body that tracks nuclear tests reported an underwater explosion near the vessel's last known position, shortly after the captain reported an electrical fault.
Families of the missing crew members have criticized Macri's government for not communicating with them and for abandoning rescue efforts.
The Navy said on November 27 that water that entered the submarine's snorkel caused its battery to short-circuit before the vessel vanished from radar.
Officials had previously said international organisations detected a noise that could have been the submarine imploding.
The search for survivors was officially abandoned on November 30, when the focus was switched to recovering wreckage.
By that time, the search had continued for double the amount of time the submarine would have had oxygen.