BUENOS AIRES, Argentina — Argentina’s navy identified a wreck off the coast of Buenos Aires province as the Ussukuma, a Nazi supply vessel that sank after an encounter with British warships in the early days of World War II.

The Ussukuma, scuttled by its crew in December 1939 after leaving the port of Bahía Blanca, was probably transporting food, fuel, and explosives for German warships, according to Argentine historian Carlos De Napoli, who helped identify the wreck.

The remains of the merchant vessel lie about 62 miles from the coastal town of Necochea at a depth of about 230 feet. The identification, confirmed in this month’s issue of the navy’s “Shipping Advisories,” is a boost to efforts by historians and Argentine authorities to identify other wartime wrecks.

“This is the first Nazi wreck to be identified in Argentine waters in decades,” Mr. De Napoli, 56, said. “We have at least six more Nazi ship and submarine wrecks waiting to be discovered.”

Argentine Naval Captain Juan de Carranza said by e-mail that Mr. De Napoli’s research helped identify what had appeared on charts as an unnamed wreck. There are no plans to salvage the ship. Another unidentified wreck is in the vicinity, maps show.

Attacks on merchant ships such as the Ussukuma were frequent throughout the war as Britain attempted to blockade Germany and end Adolf Hitler’s Third Reich, on which it had declared war in September 1939.

“Any German ship at sea after September 1939 could only operate as a fugitive,” Eric Grove, a professor of naval history at the University of Salford, England, said. “Standard procedure for those ships was to scuttle themselves if detected by enemy forces. Dozens were scuttled in the early weeks of the war.”

The sinking of the Ussukuma took place one week before the Battle of the River Plate, which was the first major naval engagement of the war and ended in the scuttling of the German heavy cruiser Admiral Graf Spee. The River Plate is an estuary between Argentina and Uruguay.

The 7,800-ton Ussukuma had little chance of fulfilling its mission of supplying warships such as the Graf Spee. According to Britain’s Naval Historical Branch, the ship’s December 4, 1939, departure from Bahía Blanca was noted by the British Naval Attaché in Buenos Aires. At least two British warships, HMS Cumberland and HMS Ajax, were in the vicinity.

“The Commodore immediately ordered the Cumberland, which was on the way south to the Falkland Islands, to search the southern arcs of the Ussukuma’s possible course,” according to U.K. naval records.

“At 19:10 on the fifth, the Ajax sighted her smoke to the north-northeast, but the Germans scuttled their ship which, in spite of the efforts of the Ajax to save her, sank during the night.”

After the Ussukuma sank, the Ajax took the 107 crew members from their lifeboats and transferred them to the Cumberland, which put them ashore on the Falklands Islands.

The Cumberland then went to the River Plate to join the Ajax and the New Zealand warship HMS Achilles, which were standing off the neutral port of Montevideo, Uruguay, where the Graf Spee had put in for repairs and fuel.

Realizing the ship couldn’t evade the British navy, the Graf Spee’s captain, Hans Langsdorff, ordered it scuttled in shallow waters on December 17.

The sinking of the Graf Spee helped boost the reputation of Winston Churchill, who was First Lord of the Admiralty at the time. Churchill referred to the victory in a January 20, 1940, broadcast speech summarizing the early months of the war.

“The Spee still sticks up in the harbor of Montevideo as a grisly monument and as a measure of the fate in store for any Nazi warship which dabbles in piracy on the broad waters,” Churchill, who became prime minister less than four months later, said.