All laborers and mechanics employed by contractors or subcontractors in the performance of construction, repair, or alteration work funded in whole or in part under this section shall be paid wages at rates not less than those prevailing on projects of a character similar in the locality as determined by the Secretary of Labor in accordance with sections
3141 through
3144,
3146, and
3147 of title
40. The Secretary shall not approve any such funding without first obtaining adequate assurance that required labor standards will be maintained upon the construction work.