In this undated file photo provided by the Argentina Navy shows an ARA San Juan, a German-built diesel-electric vessel, near Buenos Aires, Argentina. The Navy's spokesman said Monday, December 4, 2017, that U.S and Russian ships carrying remotely operated vehicles capable of deep seafloor searches are joining other vessels hunting for an Argentine submarine that went missing in the South Atlantic 19 days ago. (Photo by Argentina Navy via AP File)
