"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.
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 at a depth up to 850 feet.