Argentina's navy has launched a huge search and rescue operation for a military submarine with at least 40 crew members that has been missing off the coast of Patagonia for more than two days. The last radio contact with the San Juan submarine was on Wednesday, when it was 430km off the coast of the southern province of Chubut, in the area of San Jorge bay, a naval spokesman said on Friday. "The latest official and reliable information is that the submarine has not yet been found," said navy spokesman Enrique Balbi. A tracker aeroplane and navy ships are scouring the area in search of the missing vessel, he said. Local media reported that contact with the San Juan was lost after a fire affected the submarine's radio equipment. "We are investigating the reasons for the lack of communication," Argentine naval spokesman Enrique Balbi told reporters. "If there was a communication problem, the boat would have to come to the surface." The diesel-powered 66-metre long Class TR 1700 San Juan is one of the Argentinian navy's three submarines. It was bought from Germany in 1985. It was on a voyage from the southernmost city of Ushuaia to the naval base of Mar del Plata when contact was lost. Balbi said the submarine had enough food for several days.