Hopes that the crew of a missing Argentine submarine may still be alive look to have been dashed after the navy said an explosion had been detected.

The "abnormal, singular, short, violent, non-nuclear event" was recorded in the south Atlantic by a nuclear test watchdog.

The ARA San Juan has been missing in the South Atlantic since last week and dozens of planes and boats have been involved in the search.

Some 44 people were on board the vessel when the Argentine Navy lost contact with it.

Relatives

Yesterday, Navy spokesperson Enrique Balbi said relatives had been informed of the explosion, adding that search will continue until the fate of the crew is known.

The announcement of the explosion led to scenes of anguish amongst the dozens of relatives who have faced an agonising wait for news of their loved ones.

Relatives held their heads in their hands with others carried away in distress. Others shouted angrily at officials – accusing them of deliberately withholding the truth.

This woman's husband is a crew member:

“They did not say they were dead – but it is a logical assumption as they have been there since last Wednesday,” she said.

The blast was detected last week shortly after the submarine submarine sent its last signal.

Mr Balbi said there was no sign the explosion was linked to any attack on the vessel.

Multinational search

More than a dozen ships and planes are involved in the multinational search, with search teams combing an area of some 185,000 square miles, roughly the size of Spain.

It was reported yesterday that the search for the missing vessel had entered a “critical phase” with authorities estimating that the crew’s oxygen supplies could be running low.

The submarine had been travelling from Ushuaia, the world's southernmost city, to Mar del Plata when it reported an electrical problem just before it vanished.