First American shots fired in World War II

Determining when the first engagement of neutral United States in World War II before the attack on Pearl Harbor occurred depends on the scholar and if such actions led to formal entry of the United States into the conflict.

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

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.

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.

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