((a)) The individual Indian owners of any land which either is held by the United States in trust for them or is subject to a restriction against alienation imposed by the United States are authorized, subject to approval by the Secretary of the Interior, to execute a mortgage or deed of trust to such land. Such land shall be subject to foreclosure or sale pursuant to the terms of such mortgage or deed of trust in accordance with the laws of the tribe which has jurisdiction over such land or, in the case where no tribal foreclosure law exists, in accordance with the laws of the State or Territory in which the land is located. For the purpose of any foreclosure or sale proceeding the Indian owners shall be regarded as vested with an unrestricted fee simple title to the land, the United States shall not be a necessary party to the proceeding, and any conveyance of the land pursuant to the proceeding shall divest the United States of title to the land. All mortgages and deeds of trust to such land heretofore approved by the Secretary of the Interior are ratified and confirmed.
((b)) In the event such land is acquired by an Indian or an Indian tribe, such land shall not be removed from trust or restricted status except upon application to the Secretary under existing law.