at any military, air, or naval base acquired after January 1, 1940, by the United States from any foreign government; or

upon any lands occupied or used by the United States for military or naval purposes in any Territory or possession outside the continental United States (including the United States Naval Operating Base, Guantanamo Bay, Cuba; and the Canal Zone); or

upon any public work in any Territory or possession outside the continental United States (including the United States Naval Operating Base, Guantanamo Bay, Cuba; and the Canal Zone), if such employee is engaged in employment at such place under the contract of a contractor (or any subcontractor or subordinate subcontractor with respect to the contract of such contractor) with the United States; but nothing in this paragraph shall be construed to apply to any employee of such a contractor or subcontractor who is engaged exclusively in furnishing materials or supplies under his contract;

under a contract entered into with the United States or any executive department, independent establishment, or agency thereof (including any corporate instrumentality of the United States), or any subcontract, or subordinate contract with respect to such contract, where such contract is to be performed outside the continental United States and at places not within the areas described in subparagraphs (1)–(3) of this subdivision, for the purpose of engaging in public work, and every such contract shall contain provisions requiring that the contractor (and subcontractor or subordinate contractor with respect to such contract) (1) shall, before commencing performance of such contract, provide for securing to or on behalf of employees engaged in such public work under such contract the payment of compensation and other benefits under the provisions of this chapter, and (2) shall maintain in full force and effect during the term of such contract, subcontract, or subordinate contract, or while employees are engaged in work performed thereunder, the said security for the payment of such compensation and benefits, but nothing in this paragraph shall be construed to apply to any employee of such contractor or subcontractor who is engaged exclusively in furnishing materials or supplies under his contract;

under a contract approved and financed by the United States or any executive department, independent establishment, or agency thereof (including any corporate instrumentality of the United States), or any subcontract or subordinate contract with respect to such contract, where such contract is to be performed outside the continental United States, under the Mutual Security Act of 1954, as amended (other than title II of chapter II thereof unless the Secretary of Labor, upon the recommendation of the head of any department or other agency of the United States, determines a contract financed under a successor provision of any successor Act should be covered by this section), and not otherwise within the coverage of this section, and every such contract shall contain provisions requiring that the contractor (and subcontractor or subordinate contractor with respect to such contract) (A) shall, before commencing performance of such contract, provide for securing to or on behalf of employees engaged in work under such contract the payment of compensation and other benefits under the provisions of this chapter, and (B) shall maintain in full force and effect during the term of such contract, subcontract, or subordinate contract, or while employees are engaged in work performed thereunder, the said security for the payment of such compensation and benefits, but nothing in this paragraph shall be construed to apply to any employee of such contractor or subcontractor who is engaged exclusively in furnishing materials or supplies under his contract;

outside the continental United States by an American employer providing welfare or similar services for the benefit of the Armed Forces pursuant to appropriate authorization by the Secretary of Defense,

the term “public work” means any fixed improvement or any project, whether or not fixed, involving construction, alteration, removal or repair for the public use of the United States or its allies, including but not limited to projects or operations under service contracts and projects in connection with the national defense or with war activities, dredging, harbor improvements, dams, roadways, and housing, as well as preparatory and ancillary work in connection therewith at the site or on the project;

the term “allies” means any nation with which the United States is engaged in a common military effort or with which the United States has entered into a common defensive military alliance;

the term “war activities” includes activities directly relating to military operations;

the term “continental United States” means the States and the District of Columbia.