First engagement of neutral United States in World War II before the attack on Pearl Harbor

• On 22 February 1932 while delivering a China Republic biplane, US Lt [Reserve] Robert McCawley Short is killed in aerial combat with IJN aircraft.
• On 20 August 1937 In a friendly fire incident Chinese artillery strikes USS Augusta (CA-31) killing seaman 2/c F.J. Falgout of Raceland, Louisiana[1] and wounding 18.[2]
• On 31 August 1937 In a friendly fire incident Chinese warplanes accidentally attack SS President Hoover killing Mess Steward S. Haskell[3] and wounding 1 crewman and six passengers.[4]
• On 30 November 1937 the American tugboat Felting at the French concession at Shanghai is seized by the Japanese; the U.S. Flag is thrown overboard and a wooden plaque on the ships origin is torn off and used to strike a Chinese crewman; the tug was "returned" 1 December 1937.[5]
• On 12 December 1937 the attack on the United States gunboat USS Panay by Japanese forces in China (usually referred to as the Panay incident) could be considered as the first hostile American action during World War II. Two U.S. Navy crewmen and two civilians were killed; 43 Navy crewmen and five civilians were wounded. Although the war was not officially declared in Europe until Germany invaded Poland on 1 September 1939, Japan had been involved in military actions against China since 1931.
• On 26 January 1938, in what was known as the Allison incident, John M. Allison, at the time consul at the American embassy in Nanking, was struck in the face by a Japanese soldier. Even though the Japanese apologized formally on 30 January (after the Americans demanded they do so), this incident, together with the looting of American property in Nanking that took place at the same time, further strained relations which had already been damaged by the Panay incident less than two months earlier.
• On 24 August 1938 in the Kweilin incident a CNAC DC-2 at Zhongshan China was strafed by Japanese fighters; American pilot Hugh Leslie Woods was one of only 3 survivors of 17 passengers and crew; the plane was later destroyed on 29 October 1940 as CNAC DC-2 number 39
• On 3 September 1939 SS Athenia was the first British liner to be torpedoed and sunk after Britain declared war on Germany, by U-30. Total casualties were 112, including 28 US citizens.[6]
• On 21 April 1940 the first American military death in the European Theatre occurred during the German invasion of Norway.[7] Military attaché Captain Robert M. Losey was killed during a German bombardment of Dombås while assisting with the evacuation of U.S. embassy personnel and others to Sweden.[7]
• On 29 October 1940 CNAC DC-2 number 39 was attacked by Japanese Fighter planes at rural Changyi Airfield in Yunnan; American Pilot Walter "Foxie" Kent killed along with 1 crew and 7 passengers.
• On 4 September 1941 during the "Greer Incident" the destroyer USS Greer was fired upon with torpedoes by U-652.
• On 18 October 1941 HMS Broadwater was sunk by U-101. Among the fatalities was Lt John Stanley Parker RNVR an American [8]
• Either the casualties inflicted on USS Kearny by U-568 on 17 October 1941 (11 KIA)[9] or the sinking of the USS Reuben James by U-552 on 31 October 1941, (115 KIA)[10] might be considered the first American naval losses of World War II. The United States was neither officially involved in the war at the time nor did the incidents cause it to declare war.

The first American hostile action against Axis forces was on 10 April 1941, when the destroyer USS Niblack attacked a German U-boat: the U-52, which had just sunk the Dutch freighter Saleier[11] near Iceland. Niblack was picking up survivors of the freighter when it detected U-52 preparing to attack. The Niblack attacked with depth charges and drove off the U-boat. There were no casualties on board Niblack or the U-boat. By coincidence, USS Niblack was later in the same convoy as, and picked up survivors from, the USS Reuben James when that ship was sunk.

The first American hostile action against Axis forces that resulted in physical destruction was on 14 September 1941, when USCGC Northland destroyed a German weather station in northeast Greenland. The action was based on an agreement with Danish Ambassador to the United States Henrik Kauffmann in April 1941 to patrol the Danish island.[12]

The first American-caused casualties occurred on 7 December 1941 when the USS Ward attacked and sank a Japanese midget submarine near the entrance to Pearl Harbor prior to the commencement of the Japanese air attack upon Hawaii later that day. As a result of the attack on Hawaii, America declared war on Japan on 8 December 1941. Germany and Italy declared war on the United States three days later.

The first planned offensive action by the United States in World War II came in January 1942 when the aircraft carrier USS Enterprise attacked Japanese bases in the Marshall Islands.

• SS Robin Moor

• USS Niblack site
• USS Ward, Report of Pearl Harbor Attack Naval History & Heritage Command