The Argentine Navy announced on Saturday that it was ramping up the hunt for a submarine that disappeared three days previously, despite the rough weather hampering the search. At least six other nations have offered to aid in the mission to recover the vessel and the 44 crew members aboard.
"The weather is bad. There is a storm with waves of six meters (nearly 20 feet)," navy spokesman Enrique Balbi said at a press conference. "It really complicates the work."
The ARA San Juan, a TR-1700 class diesel electric submarine, was last heard from Wednesday morning. The vessel was returning from a routine mission to the southern tip of South America on its way back to its base at Mar del Plata, some 400 kilometers (240 miles) south of Buenos Aires. The last point of communication was off the coast of Chubut in the country's south.
Balbi initially theorized that the vessel had suffered an electrical outage, which would account for its lack of communication.
One of the crew on board was 35-year-old Eliana Krawczyk, Argentina's first female submarine officer.
Massive international search
Argentina immediately launched a sea and air hunt for the submarine. According to Balbi, "nearly 50 percent" of the search area has already been surveyed by ships and aircraft.
President Mauricio Macri wrote on Twitter that he would call upon "all resources national and international that are necessary to find the submarine."
The governments of Chile, Uruguay, Brazil and Peru have all pledged their help, while the United States has sent a NASA scientific aircraft to help in the search. Britain sent its polar expedition vessel the HMS Protector, which was set to arrive early Sunday.
One of the three submarines in Argentina's fleet, the ARA San Juan was built in Germany in 1983. It was re-built between 2007 and 2014 and expected to continue in operation for a further 30 years.
Source