MAR DEL PLATA, Argentina (AP) — An apparent explosion occurred near the time and place an Argentine submarine went missing, the country's navy reported Thursday, prompting relatives of the vessel's 44 crew members to burst into tears and some to say they had lost hope of a rescue.

Navy spokesman Enrique Balbi said the search will continue until there is full certainty about the fate of the ARA San Juan, despite the evidence of an explosion and with more than a week having passed since the submarine disappeared. It was originally scheduled to arrive Monday at Argentina's Mar del Plata Navy Base.

The U.S. Navy and an international nuclear test-ban monitoring organization said a "hydro-acoustic anomaly" was produced just hours after the navy lost contact with the sub on Nov. 15. It was near the submarine's last known location.

"According to this report, there was an explosion," Balbi told reporters. "We don't know what caused an explosion of these characteristics at this site on this date."

The navy spokesman described the "anomaly" as "singular, short, violent and non-nuclear."

Relatives of the crew who had gathered at the Mar del Plata base to receive psychological counseling broke into tears and hugged each other after they received the news. Some fell on their knees or clung to a fence crowded with blue-and-white Argentine flags, rosary beads and messages of support. Most declined to speak, while a few others lashed out in anger at the navy's response.

"They sent a piece of crap to sail," said Itati Leguizamon, wife of submarine crew member German Suarez. "They inaugurated a submarine with a coat of paint and a flag in 2014, but without any equipment inside. The navy is to blame for its 15 years of abandonment."

Balbi defended the Argentine Navy, saying that "with respect to the maintenance and state of our naval and air units, no unit ever leaves port or takes off if it isn't in operating conditions to navigate or fly with total security."

The German-built diesel-electric TR-1700 class submarine was commissioned in 1985 and was most recently refitted in 2014.

During the $12 million retrofitting, the vessel was cut in half and had its engines and batteries replaced. Experts say that refits can be difficult because they involve integrating systems produced by different manufacturers and even the smallest mistake during the cutting phase of the operation can put the safety of the ship and the crew at risk.

The Argentine navy and outside experts have said that even if the ARA San Juan is intact, its crew might have only enough oxygen to be submerged seven to 10 days. It lost contact as it was sailing from the extreme southern port of Ushuaia. The submarine's captain had reported a battery failure.

Authorities said late Wednesday that Argentine navy ships as well a U.S. P-8 Poseidon aircraft and a Brazilian air force plane would return to the area to check out the abnormal sound, which originated about 30 miles north of the submarine's last registered position.

The search location straddles the edge of the continental shelf, with widely varying ocean depths, some as great as 10,000 feet (3,000 meters). Experts say the submarine could not have supported pressures that far down.

"If a submarine goes below its crush-depth, it would implode, it would just collapse," said James H. Patton Jr. a retired Navy captain. "It would sound like a very, very big explosion to any listening device."

Whatever it was, U.S. Navy Lt. Lily Hinz said the sound detected "was not a whale, and it is not a regularly occurring sound."

Claudio Rodriguez, brother of crew member Hernan Rodriguez, said his family suspects "the explosion was so strong that they were not able to rise to the surface or shoot any flares. They didn't have time for anything."

"As a family, we're grateful to all the people who prayed for us and for the families of all the 44," he said.

More than a dozen airplanes and ships have been participating in the multinational search despite stormy weather that has caused waves of more than 20 feet (6 meters). Search teams are combing an area of some 185,000 square miles (480,000 square kilometers), which is roughly the size of Spain.

The U.S. government has sent two P-8 Poseidons, a naval research ship, a submarine rescue chamber and sonar-equipped underwater vehicles. U.S. Navy sailors from the San Diego-based Undersea Rescue Command were also helping with the search.

Britain's Ministry of Defense sent a special airplane with emergency life support pods to join the hunt that includes planes and ships from a dozen nations.

Hopes were buoyed after brief satellite calls were received and when sounds were detected deep in the South Atlantic. But experts later determined that neither was from the missing sub.

"They haven't come back and they will never come back," said Jesica Gopar, wife of submarine officer Fernando Santilli, choking back tears. "I had a bad feeling about this and now it has been confirmed."

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Henao reported from Buenos Aires. AP writer Julie Watson in San Diego and Mayra Pertossi, Debora Rey and Victor Caivano in Buenos Aires and AP video journalist Paul Byrne in Mar del Plata contributed to this report.