The British force, comprising the cruisers HMS Exeter (8" guns), HMS Ajax and HMNZS Achilles (both 6" guns), engaged the battleship close to the estuary of the Rio de la Plata, or River Plate, between Argentina and Uruguay. Following intense gunnery action where the battleship had the advantage of longer range guns, while the British were able to divide fire, the Graf Spee eventually headed for Montevideo harbour in Uruguay.
Exeter had been severely damaged in the battle, and British propaganda efforts were made to convince Captain Hans Langsdorff of the Graf Spee that an overwhelming British force was being assembled, when in fact only the Exeter's sister-ship HMS Cumberland was available and was being sent from the Falkland Islands.
Intense negotiations were undertaken, Uruguay being neutral. While the ship was prevented from leaving the harbour, Captain Langsdorff consulted with his command in Germany. He received orders that permitted various options, but not internment. He chose to scuttle his ship in the Rio de la Plata estuary (December 17) to avoid risk to the crew, a decision that is said to have infuriated Hitler. The crew of the Graf Spee was taken to Buenos Aires, where Captain Langsdorff subsequently committed suicide.
The prisoners taken by the Graf Spee prior to her sinking of
enemy ships were transferred to her German supply ship Altmark,
from which they were freed (February 16, 1940) by a boarding party from
the British destroyer HMS Cossack while in Jøssingfjord, in neutral
Norwegian waters.