Whenever the President finds and declares that at any place or within any area on the high seas adjacent to but outside customs waters any vessel or vessels hover or are being kept off the coast of the United States and that, by virtue of the presence of any such vessel or vessels at such place or within such area, the unlawful introduction or removal into or from the United States of any merchandise or person is being or may be occasioned, promoted, or threatened, the place or area so found and declared shall constitute a customs-enforcement area for the purposes of this Act. Only such waters on the high seas shall be within a customs-enforcement area as the President finds and declares are in such proximity to such vessel or vessels that such unlawful introduction or removal of merchandise or persons may be carried on by or to or from such vessel or vessels. No customs-enforcement area shall include any waters more than one hundred nautical miles from the place or immediate area where the President declares such vessel or vessels are hovering or are being kept and, notwithstanding the foregoing provision, shall not include any waters more than fifty nautical miles outwards from the outer limit of customs waters. Whenever the President finds that, within any customs-enforcement area, the circumstances no longer exist which gave rise to the declaration of such area as a customs-enforcement area, he shall so declare, and thereafter, and until a further finding and declaration is made under this subsection with respect to waters within such area, no waters within such area shall constitute a part of such customs-enforcement area. The provisions of law applying to the high seas adjacent to customs waters of the United States shall be enforced in a customs-enforcement area upon any vessel, merchandise, or person found therein.
At any place within a customs-enforcement area the several officers of the customs may go on board of any vessel and examine the vessel and any merchandise or person on board, and bring the same into port, and, subject to regulations of the Secretary of the Treasury, it shall be their duty to pursue and seize or arrest and otherwise enforce upon such vessel, merchandise, or person, the provisions of law which are made effective thereto in pursuance of subsection (a) in the same manner as such officers are or may be authorized or required to do in like case at any place in the United States by virtue of any law respecting the revenue: Provided, That nothing contained in this section or in any other provision of law respecting the revenue shall be construed to authorize or to require any officer of the United States to enforce any law thereof upon the high seas upon a foreign vessel in contravention of any treaty with a foreign government enabling or permitting the authorities of the United States to board, examine, search, seize, or otherwise to enforce upon such vessel upon the high seas the laws of the United States except as such authorities are or may otherwise be enabled or permitted under special arrangement with such foreign government: Provided further, That none of the provisions of this Act shall be construed to relieve the Secretary of Commerce of any authority, responsibility, or jurisdiction now vested in or imposed on that officer.