Amid reports a missing Argentine submarine tried unsuccessfully to contact naval bases seven times, a top navy officer said Sunday there is no indication the calls came from the ARA San Juan.
"The calls are being analyzed, but we do not have clear evidence that they came from that unit," said Gabriel Gonzales, who is in charge of the base where the submarine was slated to arrive Sunday, according to state-run news agency Télam.
Earlier Sunday, the country's defense ministry said the calls came to different bases between 10:52 a.m. and 3:42 p.m. Saturday, and lasted between four and 36 seconds, the ministry said in a statement to CNN en Español.
"We received seven satellite calls that likely came from the submarine San Juan. We are working hard to locate it. To the families of the 44 crew members: We hope you'll have them home soon," Argentina's Defense Minister Oscar Aguad tweeted.
The military is working with a US company that specializes in satellite communication to determine the location of the submarine that vanished three days ago.
The ARA San Juan submarine and its 44 crew members were traveling through the Atlantic Ocean from a base in southern Argentina's Tierra del Fuego archipelago to their home port in Mar del Plata. The sub was scheduled to arrive at its destination Sunday.
The submarine was last spotted Wednesday in the San Jorge Gulf, a few hundred kilometers off the coast of southern Argentina's Patagonia region and nearly midway between the bases.
As officials await word on the submarine, relatives of crew members gathered Saturday for Mass at a navy base in Mar del Plata, where they prayed for their safe return.
Southern Argentina's Patagonia coast is notorious for strong storms.
"Currently a powerful low-pressure system is causing wind gusts in excess of 70 kph (nearly 45 mph) and churning up the South Atlantic Ocean with swells equivalent to a two-story building. This weather will hamper the search efforts for at least the next 48 hours," CNN Meteorologist Derek Van Dam said.
The Argentine navy said it ordered stations along the coast to search their communications and listen into all possible frequencies of the submarine."
The San Juan is a 65-meter-long (213 ft) TR-1700 submarine, powered by one electric and four diesel engines, Argentina's military said.
The US Navy said Saturday it ordered its Undersea Rescue Command based in San Diego to deploy to Argentina to help with the search.
The first rescue system -- the submarine rescue chamber and an underwater, remotely operated vehicle -- was flown from Miramar to Comodoro Rivadavia, Argentina, where it's expected to arrive Sunday.
The second rescue system and supporting equipment will be transported using additional flights, and is scheduled to arrive in Argentina next week, the navy said in a statement.
The systems allow the safe underwater transfer of sailors from a submarine.
A P8-A Poseidon -- a maritime, patrol and reconnaissance aircraft -- has arrived in Argentina, along with a NASA P-3 Orion aircraft, the statement said. In another statement Sunday, the Navy said it was sending another P8-A Poseidon and 21 crew members to join the search effort.
The P-3 is a turboprop aircraft capable of long-duration flights, according to NASA.
Britain's Royal Navy said its patrol ship, the HMS Protector, is also joining search and rescue efforts at the request of the Argentine government. It said the ice patrol ship has sonar equipment to search beneath the waves.
The ship is speeding toward the search area, and is expected to arrive Sunday morning, said Capt. Angus Essenhigh, its commanding officer. He said rescue efforts are expected to start as soon as the team arrives.