Satellite calls that had raised hopes of finding a submarine that has been lost at sea for five days did not come from the 44 crew members on board, the Navy said Monday, complicating an international rescue effort that has already been hindered by stormy weather.
Officers revealed however that the ARA San Juan, missing now for five days, reported a mechanical breakdown in its final communication. The nature of the breakdown was not immediately clear. It was the first time the Navy indicated it had been aware of a problem.
"The vessel surfaced and it reported a breakdown. It was therefore asked to change course and go to Mar del Plata," said Gabriel Galeazzi, the head of the naval base in the northeastern city, located 400 kilometres (250 miles) south of Buenos Aires.
The CNN news channel reported Monday that Navy had detected noises that could be distress signals from the crew of the missing submarine. The noises sounded like tools being banged on the hull of a submarine, CNN cited a senior official in the US Navy familiar with the search as saying.
Authorities last had contact with the ARA San Juan sub on Wednesday as it journeyed from the southern port of Ushuaia to the coastal city of Mar del Plata. Dozens of aircraft and ships, including a British polar exploration vessel, have joined in search efforts that have attracted the world's attention.
The communication attempts received on Saturday were originally thought to indicate that the crew was trying to re-establish contact, prompting emotional celebrations by family members and officials. But Navy spokesman Enrique Balbi said Monday that officials had analysed the seven low-frequency satellite signals and determined they were not received from the submarine.
"We've received the report from the company that analszed the signals – the seven attempted calls did not come from the submarine's satellite phone," he said, adding: "We have still been unable to contact them."
Admiral Gabriel González of the Mar del Plata Naval Base confirmed Monday that the submarine had reported an electrical problem Wednesday and was returning to the base when it went missing in the South Atlantic.
The ARA San Juan, a German-built diesel-electric sub, made its last contact on Wednesday. The A multinational air and sea search is under way with help from countries including Brazil, Britain, Chile, the United States and Uruguay.
The last few days have been difficult for the relatives of sailors aboard the sub, around 100 of whom are being housed at the Mar del Plata naval base as they await news of the crew.
"They have a lot of hope. The hours go by and the worry rate goes up. The best tranquiliser is accurate information," said Enrique Stein, a member of a psychological support cell set up for the families.
"We don't know anything. We are waiting with a great deal of anxiety," said Andrea Ali, wife of Franco Ali, an electrician aboard the San Juan.
The submarine's fate has gripped the nation, and President Mauricio Macri visited the relatives and prayed with them on Monday. The president was briefed on the search by Vice-Admiral Miguel Angel Mascolo during his visit to the base.
On Sunday, a flag was unfurled at the naval base that read: "Be strong Argentina, We trust in God, We wait for you."
At the Vatican, Argentine Pope Francis said that he is sending "fervent prayers" for the crew. Relatives of the crew members also took to social media on Monday to ask for support during the search.
"Pray so that my husband, Fernando Santilli can return home," Jesica Gopar posted on Twitter. "He's in the San Juan submarine."
President Mauricio Macri met with family members there who anxiously waited for news about their loved ones.
"We can make up a thousand movies with happy and sad endings, but the reality is that the days pass by and not knowing anything, kills you," said Carlos Mendoza, the brother of submarine officer Fernando Ariel Mendoza.