To execute mortgages upon, or deeds of trust to, the lands within said Hopi Industrial Park. Such lands shall be subject to foreclosure or sale pursuant to the terms of such mortgage or deed to trust in accordance with the laws of the State of Arizona. The United States shall be an indispensable party to, and may be joined in, any such proceeding involving said lands with the right to remove the action to the United States district court for the district in which the land is situated, according to the procedure in section
1446 of title
28, and the United States shall have the right to appeal from any order of remand entered in such action.