>> As the search for a missing Argentine submarine ramps up Thursday, the country's Navy says the sound consistent with an explosion was detected in the South Atlantic Ocean around the same time the vessel sent its last signal.>>
> We received information of an abnormal, singular, short, violent, non-nuclear event that was consistent with an explosion.
>> The Navy captain said they have yet to determine the cause of the so-called explosion, or whether the ARA San Juan with 44 crew onboard could have been attacked on November 15th. Reuters correspondent Luc Cohen has more.>> So the Argentine Navy learned about the sound this morning from an antinuclear test group based in Austria, which has a network of sensors in oceans all around the world.
>> But Cohen says there are still many unanswered questions.>> It's still not known whether the submarine was attacked or if the sound that appears to be an explosion even sunk the submarine. There's still a lot of concern about the fate of the 44 crew members aboard.>> Relatives camped out at the Mardel Plada naval base, shed tears, and insulted authorities after being briefed about the possible explosion.
They're also aware that the submarine could be near the last of its seven day oxygen supply. The submarine was on route to Mardel Plada when it reported an electrical malfunction shortly before disappearing last week, prompting a massive search effort in a race against the clock.