The Argentinian Navy has detected seven satellite calls made to different bases from a missing submarine which disappeared on November 15 in the South Atlantic with 44 crew members on board, officials said.

According to a statement released on Saturday by the Argentine Ministry of Defence, the calls did not link up with the Navy bases, but could indicate that the crew on board the ARA San Juan was trying to re-establish contact, reports Efe news.

“With the collaboration of a US company specializing in satellite communication, we are now working to determine the precise location of the transmitter of the signals, given the presumption that it could be the submarine carrying 44 crew members on board,” the statement said.

The calls were made between 10.52 a.m. and 3.42 p.m., on November 15 and now the government was working to determine their exact location.

The communication attempts lasted between four and 36 seconds.

The last known position of the ARA San Juan was in the area of the San Jorge Gulf in southern Patagonia and some 432 km from the coast, the ministry said.

The German built, diesel powered submarine had left the southern port of Ushuaia on November 13 and was heading back to his base in Mar del Plata, near Buenos Aires.

The search and rescue operation, which is led by the Argentine Navy, is aided by an US NASA P-3 anti-submarine aircraft, as well as numerous Navy ships with helicopters on board.

All terrestrial communications stations along the Argentine coast were ordered to search for communications and listen to all possible frequencies of transmission of the submarine in order to make a contact.

President Mauricio Macri said on Saturday that the government was committed to using “all national and international resources” to locate “as soon as possible” the 44 crew members of the ship.