Fears for the 44 crew members of the missing Argentine submarine ARA San Juan deepened dramatically as the country's navy said a "violent event consistent with an explosion" had been detected three hours after the vessel disappeared in the South Atlantic.

Search vessels were combing an area with a 130km radius close to the submarine's last known position, after analysis from the US and Austria revealed a "hydroacoustic anomaly" on the morning that the ARA San Juan lost contact after reporting a fault with its batteries, the Telegraph UK reports.

Navy spokesman Captain Enrique Balbi confirmed "a singular event, short, violent, non nuclear, consistent with an explosion" had happened about 50km north of where the submarine disappeared.

Eight days into the search, the revelation of the apparent explosion led to cries of anger from waiting relatives.

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Speaking outside the Mar del Plata Naval Base, Itati Leguizmon, wife of radarist German Oscar Suarez, said she felt "deceived" by Navy officials, who she alleged had "lied to us" and withheld information on the missing submarine. Some relatives had become "aggressive" when they were informed, Leguizmon said, and were "breaking things" inside the base.

Balbi defended the delay amid a barrage of questions. He insisted the report from the United States had only been "officially" received on Wednesday and the second from Austria - which offered more details on the source of the anomaly.

The "hydroacoustic anomaly" was recorded by hydrophones - listening posts scattered around the world's oceans capable of detecting underwater noise - and had to be collated, analysed and checked, the spokesman explained.

The ARA San Juan had previously reported a short-circuit in its batteries and been ordered to divert to the Mar del Plata naval base. The purported explosion was on the route it is likely to have taken.

Balbi said an explosion inside the submarine could have caused it to implode, which could explain why no debris had been found.