U-boat operations in the region (centered in the Atlantic Narrows between Brazil and West Africa) began in autumn 1940. After negotiations with Brazilian Foreign Minister Osvaldo Aranha (on behalf of dictator Getúlio Vargas), the U.S. introduced its Air Force along Brazil's coast in the second half of 1941. Germany and Italy subsequently extended their submarine attacks to include Brazilian ships wherever they were, and from April 1942 were found in Brazilian waters. On 22 May 1942, the first Brazilian attack (although unsuccessful) was carried out by Brazilian Air Force aircraft on the . After a series of attacks on merchant vessels off the Brazilian coast by , Brazil officially entered the war on 22 August 1942, offering an important addition to the Allied strategic position in the South Atlantic. Although the Brazilian Navy was small, it had modern minelayers suitable for coastal convoy escort and aircraft which needed only small modifications to become suitable for maritime patrol. During its three years of war, mainly in Caribbean and South Atlantic, alone and in conjunction with the U.S., Brazil escorted 3,167 ships in 614 convoys, totalling 16,500,000 tons, with losses of 0.1%. Brazil saw three of its warships sunk and 486 men killed in action (332 in the cruiser "Bahia"); 972 seamen and civilian passengers were also lost aboard the 32 Brazilian merchant vessels attacked by enemy submarines. American and Brazilian air and naval forces worked closely together until the end of the Battle. One example was the sinking of in July 1943, by a coordinated action of Brazilian and American aircraft. Only in Brazilian waters, eleven other Axis submarines were known sunk between January and September 1943—the Italian "Archimede" and ten German boats: , , , , , , , , , and .