On Thursday, the Argentinian Navy has concentrated its efforts to find the missing submarine in the area where a sound consistent with an explosion was recorded, spokesman Enrique Balbi said Thursday.
Ten ships and three aircraft have been scouring the designated area in the South Atlantic, the Navy said in a statement, adding search efforts were also continuing in other areas, "although without favorable results."
Meantime, relatives of the 44 missing crew members who were aboard a submarine when it vanished in the ocean lashed out at the Navy on after the hope of finding them alive dimmed.
Claudio Rodriguez, whose brother was on board the sub, told Sputnik he had expressed his frustration to the admiral in charge of the Mar del Plata naval base, the submarine’s destination.
"I told the admiral that if they are responsible for what has happened to my brother, a national hero, and other crew, we expect that they pay for this," Rodriguez said.
The aircraft described by the Todo Noticias news channel appears to be an Antonov An-124 Ruslan, which can carry up to 150 tonnes of cargo and special equipment.
Russian President Vladimir Putin called his Argentinian counterpart Mauricio Macri on Wednesday to offer him assistance of a Russian high-tech oceanographic vessel. The Argentinian leader had thanked Russia for help.
Russia has become the thirteenth country to join the operation to rescue the missing ARA San Juan submarine.
Meanwhile, families and friends of the sailors have gathered in Mar del Plata to wait for the news about the fate of ARA San Juan, after it disappeared off the radar more than a week ago. The missing vessel had reportedly enough oxygen to last for six days.