Argentina says it's not giving up yet on missing sub.

Explosion feared as clock ticks past the time when oxygen was expected to run out for the 44-strong crew

epa06352898 Argentinian Army's spokesperson Enrique Balbi delivers a press conference in Buenos Aires, Argentina, 26 November 2017. A ship with a US mini-submarine on board joined the search of the ARA San Juan, which was last heard from on 15 November 2017.  EPA/Javier Caamano

Argentina's navy is not giving up hope that crew members could be alive 11 days after a submarine vanished off the Atlantic coast with 44 people aboard.

Navy spokesman Enrique Balbi told a news conference on Sunday the passage of time does not rule out "a situation of extreme survival".

Officials say they fear there was an explosion involving the vessel that lost contact on November 15.

Experts say the ARA San Juan had only about 10 days of oxygen supply at the outside.

It had been expected to dock on November 19 in the port of Mar del Plata.

So far there has been no sign of the sub, but Mr Balbi said the multinational search effort is continuing.