A district court of the United States shall have jurisdiction to enforce, and to prevent and restrain any person from violating, this chapter or an order or regulation issued by the Secretary under this chapter.

A civil action brought under subsection (a) shall be referred to the Attorney General for appropriate action, except that the Secretary is not required to refer to the Attorney General a violation of this chapter, or an order or regulation issued under this chapter, if the Secretary believes that the administration and enforcement of this chapter would be adequately served by administrative action under subsection (c) or suitable written notice or warning to the person who committed or is committing the violation.