Can Neutral USN attack U-Boats?

[EdwinP]

Can neutral USN ships attack U-boats in the Atlantic within a "Pan-American Security Zone"? Or after a specific mobilization level is reached?

Can they move freely in the Atlantic without being attacked by Axis units, thus being used to spot U-Boats for Britain.

Greer Incident (September 1941)

The U.S. destroyer Greer provided the turning point for the developing war in the North Atlantic. The action the Greer was in fact muddled.
The Greer's captain decided to follow the U-boat for more than an hour. It signaled the British bomber with sonar readings which allowed the bomber to drop depth charges without result. The bomber returned to base. Greer continued the pursuit allowing another British bomber to drop depth charges, again without result. After 4 hours the U-boat captain smarting from the depth charges and fearing his batteries might run out, forcing him to the surface, fired two torpedoes at Greer. It is unclear if he knew he was firing at an American ship or if he was aware who had dropped the depth charges. Both torpedoes missed.

Shoot on Site Order (September 11)

President Roosevelt declared that the U-boat attack on the Greer was "piracy" (September 11). As a result of the Greer incident, the President ordered the U.S. Navy to "shoot-on-sight" any German or Italian ships found in protected zones. "The Greer was flying the American flag. Her identity as an American ship was unmistakable.... She was then and there attacked by a submarine. design to sink her." The President described the German action as 'an act of piracy'....From now on, if German or Italian vessels of war enter the waters, the protection of which is necessary for American defense, they do so at their own peril.