If a proceeding is instituted or an action is filed by the Federal Trade Commission, alleging that a proposed acquisition violates section 18 of this title, or section 45 of this title, or an action is filed by the United States, alleging that a proposed acquisition violates such section 18 of this title, or section 1 or 2 of this title, and the Federal Trade Commission or the Assistant Attorney General (1) files a motion for a preliminary injunction against consummation of such acquisition pendente lite, and (2) certifies the United States district court for the judicial district within which the respondent resides or carries on business, or in which the action is brought, that it or he believes that the public interest requires relief pendente lite pursuant to this subsection, then upon the filing of such motion and certification, the chief judge of such district court shall immediately notify the chief judge of the United States court of appeals for the circuit in which such district court is located, who shall designate a United States district judge to whom such action shall be assigned for all purposes.