The Secretary of State may grant and issue passports, and cause passports to be granted, issued, and verified in foreign countries by diplomatic and consular officers of the United States, and by such other employees of the Department of State who are citizens of the United States as the Secretary of State may designate, and by the chief or other executive officer of the insular possessions of the United States, under such rules as the President shall designate and prescribe for and on behalf of the United States, and no other person shall grant, issue, or verify such passports. Unless authorized by law, a passport may not be designated as restricted for travel to or for use in any country other than a country with which the United States is at war, where armed hostilities are in progress, or where there is imminent danger to the public health or the physical safety of United States travellers.