; or (2) against the Secretary or the Secretary of Agriculture where there is alleged a failure of such Secretary to perform any act or duty under this Act, or to promulgate any regulation under this Act, which is not within the discretion of the Secretary concerned. The United States district courts shall have jurisdiction over actions brought under this section, without regard to the amount in controversy or the citizenship of the parties, including actions brought to apply any civil penalty under this Act. The district courts of the United States shall have jurisdiction to compel agency action unreasonably delayed, except that an action to compel agency action reviewable under section 405 may only be filed in a United States district court within the circuit in which such action would be reviewable under section 405. (b) Exceptions (1) No action may be commenced under subsection (a) before the end of the 60-day period beginning on the date the plaintiff has given notice in writing of such alleged violation to the alleged violator and the Secretary concerned, except that any such action may be brought immediately after such notification if the violation complained of constitutes an imminent threat to the environment or to the health or safety of the public. (2) No action may be brought against any person other than the Secretary or the Secretary of Agriculture under subsection (a)(1) if such Secretary has commenced and is diligently prosecuting a civil or criminal action in a court of the United States to require compliance. (3) No action may be commenced under paragraph (2) of subsection (a) against either Secretary to review any rule promulgated by, or to any permit issued or denied by such Secretary if such rule or permit issuance or denial is judicially reviewable under section 405 or under any other provision of law at any time after such promulgation, issuance, or denial is final. (c) Venue Venue of all actions brought under this section shall be determined in accordance with section 1391 of title 28,