This regulation authorizes certain categories of federal law enforcement officers to request the issuance of search warrants under Rule 41, Fed. R. Crim. P., and lists the agencies whose officers are so authorized. Rule 41(a) provides in part that a search warrant may be issued “upon the request of a federal law enforcement officer,” and defines that term in Rule 41(h) as “any government agent, * * * who is engaged in the enforcement of the criminal laws and is within the category of officers authorized by the Attorney General to request the issuance of a search warrant.” The publication of the categories and the listing of the agencies is intended to inform the courts of the personnel who are so authorized. It should be noted that only in the very rare and emergent case is the law enforcement officer permitted to seek a search warrant without the concurrence of the appropriate U.S. Attorney's office. Further, in all instances, military agents of the Department of Defense must obtain the concurrence of the appropriate U.S. Attorney's Office before seeking a search warrant.