Whenever it appears that the vessel is not entitled to clearance or whenever there is reasonable cause to believe that the additional statements under oath required in section 965 of this title are false, the collector of customs for the district in which the vessel is located may, subject to review by the head of the department or agency charged with the administration of laws relating to clearance of vessels, refuse clearance to any vessel, domestic or foreign, and by formal notice served upon the owners, master, or person or persons in command or charge of any domestic vessel for which clearance is not required by law, forbid the departure of the vessel from the port or from the United States. It shall thereupon be unlawful for the vessel to depart.