The craft was navigating normally, underwater, at a speed of five knots toward Mar del Plata when it was last heard from, he said.
"A US Navy P8 sub hunter aircraft is now flying over that square mileage".
Crew members' relatives gathered at the Mar del Plata naval base, waiting for news.
Having arrived on station early this morning we are now assisting with the search and rescue efforts and my team on board are trained and equipped to deal with this task.
Over the weekend, IARU Region 2 News Editor Joaquín Solana, XE1R, issued a list of marine frequencies, suggesting that radio amateurs and SWLs listen for any signals that could be related to the missing San Juan.
A storm has hindered an worldwide search operation for a missing Argentinian submarine as authorities try to verify whether recent satellite calls were from the submarine with 44 crew members on board.
Waves up to 20-feet in the area where the sub went missing, about 260 miles from the Argentine coast, were complicating the global search effort, Adm. Gabriel Gonzalez, commander of the base, was quoted by The Associated Press as saying. The Argentine sub has been missing in the Argentine Sea, and the subsequent search is entering its fifth day.
Rescue equipment american arrived on Sunday to Comodoro Rivadavia (Patagonia) was on Monday during assembly.
The vessel's captain reported a "failure" in the vessel's battery system shortly before it disappeared last week, Navy spokesman Gabriel Galeazzi said.
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The ARA San Juan was returning from a routine mission to Ushuaia, near the southern-most tip of South America, to its base at Mar del Plata, south of Buenos Aires. The navy did not give details of the content of that final communication.
That hope came in the form of seven signals to a satellite, which defense officials believe may have been attempts to communicate. Her father, Eduardo Krawczyk, said: "We are extremely anxious, with little news, waiting for information".
So far, 80 percent of the area initially marked for search has shown no signs of the submarine.
Stormy weather probably interfered with the calls, and the government was working with an unidentified USA company specialised in satellite communication to trace the location.
Weather conditions in the region have made the search hard, spokesmen said, with 6-8 meter (20-26 foot) waves prevailing there in recent days. Officials have said the crew should have an ample supply of food and oxygen.
Fears are growing for the sub, as if it hasn't surfaced it will be running out of air.
If it is immersed and can not raise a snorkel, oxygen may last about seven days.
The sub sent its last signal on Wednesday.
"This phase of search and rescue is critical", Balbi said. Both types are capable of deploying quickly and searching wide areas of the ocean using Side Scan Sonar, a system that is used to efficiently create an image of large areas of the sea floor.