BUENOS AIRES, Argentina -- Argentina says a U.S. undersea rescue module is arriving to an area in the South Atlantic where an Argentine submarine went missing 12 days ago with 44 crew members on board.

Navy spokesman Enrique Balbi said Monday that a Norwegian ship carrying the U.S. Navy's underwater remotely operated vehicle and its pressurized rescue module would arrive to the search zone later in the day.

The navy says an explosion occurred near the time and place where the ARA San Juan sub went missing on Nov. 15.

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Experts say the crew only had enough oxygen to last up to 10 days if the sub remained intact but submerged.

The navy says more than a dozen countries are still searching for the sub.

This video grab shows a ship sailing the Argentine Sea as seen from a P8-A Poseidon aircraft of the U.S. Navy Patrol and Reconnaissance Wing that's assisting the Argentine military in its search for the missing submarine ARA San Juan on Nov. 26, 2017. Carlos Reyes/AFP/Getty Images

The German-built diesel-electric submarine set off on a training mission on Nov. 8 from the southernmost port of Ushuaia en route to Mar del Plata.

"Two days before setting sail, there was a check of the whole operating system," Balbi said at a news conference on Saturday. "The submarine doesn't sail if that's not done. If it set off from Ushuaia, it was because it was in condition to do so."

Balbi said the captain reported on Nov. 15 that there had been an electrical problem in a battery compartment. But he later communicated by satellite phone that the problem had been solved and that he would continue the voyage submerged toward Mar del Plata.

On Monday, Balbi told reporters that a battery short-circuited when water entered the vessel through a snorkel, the Reuters news agency reports.

"They had to isolate the battery and continue to sail underwater toward Mar del Plata, using another battery," Balbi said, according to Reuters.

Since then, there has been no contact with the San Juan, and no signs of the ship or debris despite an intensive search.

But it was also on Nov. 15 that both the U.S. Navy and the international nuclear test ban monitoring agency detected what appeared to be an undersea explosion in the area where the sub was operating.

Relatives of crew members have suggested that the 33-year-old vessel, which was refitted in 2014, was in poor condition.

Hundreds of people from Mar del Plata gathered outside the naval base on Saturday to express solidarity with relatives of the crew, applauding them and shouting, "Be strong, we are with you."

Then they joined in singing the national anthem, and many embraced.

The demonstration cheered some.

"We feel supported by the people," said Zulma de Vallejos, mother of crew member Celso Oscar Vallejos. "I know my son is going to return. I know that he will come back alive. The final word hasn't been spoken."