A sound detected in the search for a missing submarine carrying 44 people is “consistent with an explosion”, Argentine officials have said.

The abnormal sound was detected in the South Atlantic ocean around the time the Argentine navy submarine sent its last communication last week.

Navy spokesman Enrique Balbi described the blast as “abnormal, singular, short, violent” and “non-nuclear”. The “hydro-acoustic anomaly,” as officials are calling it, occurred just hours after the navy lost contact with the ARA San Juan on 15 November.

“It was not a whale, and it is not a regularly occurring sound,” US navy Lieutenant Lily Hinz told Reuters.

Argentina, Brazil, and the US have sent ships and planes to investigate the noise, which occurred about 30 miles from where the submarine disappeared.

A huge sea and air hunt is being conducted for the submarine. More than a dozen countries sent planes and ships to aid in the search, which has covered some 185,000 square miles.

ARA San Juan: Relatives and Argentine Navy crew react at base Show all 14 1 /14 ARA San Juan: Relatives and Argentine Navy crew react at base ARA San Juan: Relatives and Argentine Navy crew react at base Comrades of the crew members express their grief AFP ARA San Juan: Relatives and Argentine Navy crew react at base Argentine Navy officials embrace inside the Mar de Plata Naval Base AP ARA San Juan: Relatives and Argentine Navy crew react at base People react after hearing the news AFP/Getty Images ARA San Juan: Relatives and Argentine Navy crew react at base Elena Alfaro (L), relative of missing submariner Cristian David Ibanez, arrives at Argentina's Navy base in Mar del Plata AFP/Getty Images ARA San Juan: Relatives and Argentine Navy crew react at base Relatives and comrades express their grief at the Mar del Plata Navy base AFP/Getty Images ARA San Juan: Relatives and Argentine Navy crew react at base A woman cries AP ARA San Juan: Relatives and Argentine Navy crew react at base Malvina Vallejos (C), sister of Celso Oscar Vallejos, one of the missing crew members, reacts to the news AFP/Getty Images ARA San Juan: Relatives and Argentine Navy crew react at base A woman touches a poster, overlaid with snapshots of Celso Oscar Vallejo, one of the missing crew members AP ARA San Juan: Relatives and Argentine Navy crew react at base Relatives of the 44 crew members of the missing at sea ARA San Juan submarine react REUTERS ARA San Juan: Relatives and Argentine Navy crew react at base Jessica Gopar (C), wife of Fernando Santilli, one of the missing crew members, expresses her grief AFP/Getty Images ARA San Juan: Relatives and Argentine Navy crew react at base Relatives comfort each other REUTERS ARA San Juan: Relatives and Argentine Navy crew react at base Navy workers hug each other after hearing the news of an explosion AFP/Getty Images ARA San Juan: Relatives and Argentine Navy crew react at base A woman reads the messages dedicated to the 44 crew members of the missing submarine ARA San Juan EPA ARA San Juan: Relatives and Argentine Navy crew react at base Navy members and relatives react REUTERS

One of those planes was the first RAF aircraft to land in Argentina since the Falklands War. The Voyager, carrying search equipment and life support, touched down in the southern city of Comodoro Rivadavia.

Altogether, the UK’s Ministry of Defence has sent an ice patrol ship, an offshore patrol vessel, a tactical transport aircraft, and a helicopter equipped with emergency life support pods to hunt for the German-built sub. The assistance comes some 35 years after Britain and Argentina fought a war over possession of the Falkand Islands. Nearly 1,000 military personnel on both sides were killed in the 10-week conflict.

Experts say the Argentinian vessel may only have enough oxygen to last seven to 10 days from the day it disappeared more than a week ago. Families are waiting anxiously for updates at Argentina’s Mar del Plata navy base, where the submarine was headed before it vanished.

Mr Balbi said relatives of the crew have been informed of the abnormal noise. He added that the search will continue until there is more certainty as to the vessel’s fate.

The families’ hopes were momentarily raised earlier this week when a US navy search plane detected an object in the water near where the submarine was last detected. A spokeswoman for the US embassy in Argentina later confirmed the object was not connected to the ARA San Juan.

The submarine was on a routine mission from Ushuaia – a city on the southern tip of South America – back to the Mar del Plata naval base when it vanished. The vessel surfaced shortly before its disappearance to report a short circuit in its batteries, according to naval commander Gabriel Galeazzi. It was told to return immediately to the naval base.

The morning of the disappearance, however, the sub made contact again to report that the problem had been fixed. It said it would submerge and proceed directly to the base. There has been no contact since then.