The legislation calls for a "highly effective defense of all 50 states against limited, unauthorized and accidental attacks" by nuclear missiles.

Such accidental attacks also accounted for 72 of the 467 US personnel wounded in the conflict.

They were continuing to signal their presence as neutrals- to invite inspection by Allied antisubmarine forces and avoid accidental attack.

It also downplays the chance of accidental attacks, miscalculation by military officers or theft by terrorists.

Another is China itself, which showed an ominously volatile side in its response to the accidental attack.

The military uses the term "fratricide" to describe both intentional and accidental attacks by American soldiers on each.

The British authorities have been counting 24 deaths from combat in the war, including 11 from accidental attacks by American forces.

The accidental attack comes on the heels of other notable mistakes in the alliance's air campaign, including the bombing of a hospital complex this week.

L2 survived an accidental attack by three American destroyers on 24 February 1918.

But new technologies being tested by the American-led forces have the potential to prevent many of these accidental attacks.