Notwithstanding any other law, the head of a Federal agency shall not approve any grant to, or contract or agreement with, a displacing agency (other than a Federal agency), under which Federal financial assistance will be available to pay all or part of the cost of any program or project which will result in the displacement of any person on or after , unless he receives satisfactory assurances from such displacing agency that—
((1)) fair and reasonable relocation payments and assistance shall be provided to or for displaced persons, as are required to be provided by a Federal agency under sections 4622, 4623, and 4624 of this title;
((2)) relocation assistance programs offering the services described in shall be provided to such displaced persons;
((3)) within a reasonable period of time prior to displacement, comparable replacement dwellings will be available to displaced persons in accordance with .