Families of crew lost in the San Juan submarine have been told their loved ones "are all dead" after an explosion on the day the vessel disappeared, according to reports.
Family members today claimed they had already received phone calls from Navy officials telling them the entire crew had perished in a blast, believed to have taken place between 180m and 900m below the surface.
Officially, Argentina's Navy is refusing to speculate on the fate of the sub's 44 crew members and have vowed to continue the search for the stricken vessel, according to the Daily Mail.
And they have angrily accused the Argentinian Navy of a cover-up after it was today forced to confirm there had been a violent explosion where the vessel would have been just hours after its last transmission.
The noise "consistent with an explosion" was recorded by two international agencies last Wednesday morning.
Luiz Tagliapietro, the father of Damian, who was on the submarine, claimed a Navy official phoned him to break the news that his son was dead.
Asked if the 43 men and one woman on board had died, he said: "Yes, yes, yes, yes. One hundred per cent. My son's boss confirmed that they are all dead.
"There's no human being who survives that."
Itati Leguizamon, whose husband German Oscar Suarez was on board, branded the Navy "perverse bastards" for allowing family members to continue to believe their loved ones could be found alive.
She said: "According to them, they only found out about the explosion now, but who is so stupid to believe that?
"They are a disgrace. They lied to us."
Last night the Argentinian Navy confirmed that the US government had picked up a "hydro-acoustic anomaly" under the sea about 11am last Wednesday just 30 nautical miles north of the stricken sub's last reported position.
Spokesman Enrique Balbi refused to speculate on what the noise could have been, but said ships were on their way to the site 725km off Argentina's coast.
Balbi said an "anomalous, singular, short, violent and non-nuclear event, consistent with an explosion" was heard in the area where the vessel would have been sailing last week.
It was recorded by the Comprehensive Nuclear-Test-BanTreaty Organisation, which uses a network of hydroacoustic seismic stations to monitor for possible nuclear tests.
"The two separate reports point to the same time and almost the same place," Balbi said.
"We do not know the cause [so] we will continue the search, until we find concrete evidence of where the submarine and our 44 crew members are.
"We will not draw up any hypothesis about what happened until we have the conclusive evidence to affirm it."
The news provoked outrage among desperate family members of the missing sailors who have been camped at the naval base in Mar de Plata hoping their loved ones will be found safe.
Now eight days since the submarine disappeared, their hope has turned to anger and despair amid reports oxygen supplies would have run out if there was no hull breach.
Leguizamon said her husband had gone on another mission in the same submarine in 2014, which also got into trouble because of technical problems.
She said: "The Navy tried to cover it up. But I don't care anymore, I'm going to tell everyone because I know my husband is dead. I have a lawyer and I know my rights.
"I'm trying to keep calm because my husband always me to do that. He was always ready for death, he had commended himself to God."
The Russian defence ministry said today it had sent oceanographic research vessel, the Yantar, which has been working off the western coast of Africa.
The ship "is equipped with two deep-water submersibles which allow exploratory searches at a depth of up to 6000m", Russian news agencies said.
The Yantar is a new ship that joined the Russian navy's Northern Fleet in 2015.
The submarine, which left Ushuaia in Argentina and was heading to the naval base in Mar del Plata, was last heard from as it sailed through the San Jorge Gulf, 725km from the Argentinian coast on November 15.
The 34-year-old German-built submarine had flagged a breakdown in its batteries and was ordered to return to port.
Balbi said the search was in a "critical stage" and three ships were expected to arrive soon at the area the "hydroacoustic anomaly" was heard.
News of what appears to be the last chance of finding the crew alive comes as the father of one submariner spoke poignantly about how families were 'entering into despair' over finding their loved ones alive.
Luiz Tagliapietra, the father of Alejandro who is on the sub, told the Cafe de La Tade progamme on Argentina's LN+ channel yesterday of their anguished wait for news: "It's terrible, hard to find words. I can sum it up as anguished, scared, but above all impotent."
He added: "I didn't want to talk about this to the media, I felt I had nothing to say. But now we're entering into despair. I've been almost five days without sleep.
"You go from optimism to pessimism the whole day, you hear little piece of news, you grab it, but when it's discarded it's even worse. We still don't know anything. These ups and downs are killing us."
He said Alejandro was not supposed to be on this submarine mission. He said: "It was his third or fourth trip. But he was not part of the permanent crew of this submarine, he was there just by chance, he went on it of his own accord just to learn.
"He is a shy and reserved person, but always lives his life to the full and with so much passion. And in life you have to do what you love because otherwise it is meaningless. Whatever happens, I know that he was doing what he loved."
The sub's disappearance has gripped the nation. President Mauricio Macri has visited and prayed with relatives, who have had to deal with a number of false hopes since the search began on November 16.
Underwater sounds first thought to be the crew banging on the hull were later determined to be something else.
Hopes had also briefly raised yesterday morning by reports in Argentine media that a "signal" and a "heat patch" had been detected overnight, but they turned out to be false alarms.
Britain's HMS Protector spotted three flares, Navy spokesman Captain Enrique Balbi reported, and craft equipped with sonar, infra-red and magnetic detection technology had been scrambled to the zone. But a thorough search yielded nothing, he said.
The Argentine navy said a life raft that was found in the search area on Tuesday didn't belong to the submarine and likely fell off another vessel.
The false alarms have rattled nerves among distraught family members. Some have begun to complain that the Argentine navy responded too late.
"They took two days to accept help because they minimised the situation," Federico Ibanez, the brother of submarine crew member Cristian Ibanez, told The Associated Press.
"I feel like authorities let too much time pass by and decisions were taken late," Ibanez's sister, Elena Alfaro, said outside the base. "And yet, I still carry some hope."
Many are also taking to social media to express their worries as the search continued into a second week, including Sofi Álvarez, 21, whose brother Luis Niz, 25, is on the ARA San Juan.
She tweeted: "We are here, all united, awaiting your arrival, 44 families and a very long wait. Do not stop asking, please, do not lose faith, hope. We are not going to stop until we hug them again.
"It does not matter what god you believe in, or what you believe, I only ask that with a prayer, good vibes, good energies ask for the alive appearance of the crew of the Argentine submarine ARA San Juan, one of them my eldest brother. I'm destroyed."
Speaking to MailOnline, she added: "We always talk to him before he leaves port and he did not give us any indication of a breakdown, on the contrary, he told me that in a few days we would see each other.
"He is about to get married in a few weeks."
From the Vatican, Argentine Pope Francis said he was making "fervent prayers" for the crew, and prayers have also come from legendary footballer Diego Maradona.
"I want to send strength and hope to all the relatives of the crew of the ARA San Juan submarine,' Maradona wrote on his official Instagram account.
"I think it's great that we are receiving help from other countries with better technology. And, although I wonder about those responsible for this situation, I think that today the most important thing is to rescue our boys."
This comes after one of the crew members reportedly warned her family that there had been issues on board, just days before it vanished.
Krawczyk's brother has since revealed that she called the family before they set off and told them there was a mechanical problem.
Speaking to Argentine radio and newspapers, Roberto Krawczyk has said his sister told him that the submarine had needed repairs while in port.
Storms have complicated efforts to find the navy submarine.