Argentina can't be sure satellite calls came from lost submarine amid search

Argentina's navy said Sunday that there was no clear evidence that satellite communications initially believed to have come from a submarine with 44 crew members missing in the Atlantic were from the vessel.

"We analyzed these signals, which as we know were intermittent and weak", said Gabriel Galeazzi, a naval commander.

The communication attempts "indicate that the crew is trying to re-establish contact, so we are working to locate the source of the emissions", the Navy said on its Twitter account, adding that the calls lasted between four and 36 seconds.

At the entrance of the base, locals hung signs with messages in support of the crew members and their families on a chain-link fence.

The calls revived hopes the submarine had surfaced, but a powerful storm whipped up waves reaching seven metres in height has made geolocation difficult, officials said.

The task of the rescuers has been complicated by heavy winds and high waves. Its protocol is to surface if there's a communications blackout.

The crew's relatives have gathered at the Mar del Plata Naval Base in anticipation of hearing news about their loved ones. She told a TV interviewer that she spoke to her son minutes before the submarine left Ushuaia on Monday.

The US has sent a Nasa aircraft and a navy plane to assist search efforts, while Britain dispatched the HMS Protector, a polar exploration ship.

According to the US Southern Command: 'The aircraft and its 21-person crew will depart El Salvador's Comalapa Air Base, where it was supporting counter-illicit trafficking maritime patrol operations.

"They've got to be afloat".

An Argentine destroyer and two corvettes are conducting a search around the area of the sub's last known position off the south-eastern Valdez peninsula.

The 213-foot long submarine was built in 1983 by Germany's Thyssen Nordseewerke.

The Argentine military submarine ARA San Juan and crew are seen leaving the port of Buenos Aires in a file photo. However, it underwent a seven-year refit between 2007 and 2014 to extend its life by a further 30 years.

Argentine-born Pope Francis mentioned the missing vessel in his Sunday noon prayer. A Navy inquiry found that the cause of the sinking "cannot be definitively ascertained" - and the cause of the sub's demise remains fuzzy decades later.

Iridium Communications satellite operator said Monday that it had detected no calls from missing Argentinian submarine San Juan since Wednesday, but pointed out that there could be another company's equipment aboard.