§2441. War crimes
(1) In general.—No prosecution for an offense described in subsection (a) shall be undertaken by the United States except on written certification of the Attorney General, the Deputy Attorney General, or an Assistant Attorney General, which function of approving prosecutions may not be delegated, that a prosecution by the United States is in the public interest and necessary to secure substantial justice.
(a) The Court shall have the authority to make requests to States Parties for cooperation. The requests shall be transmitted through the diplomatic channel or any other appropriate channel as may be designated by each State Party upon ratification, acceptance, approval or accession. Subsequent changes to the designation shall be made by each State Party in accordance with the Rules of Procedure and Evidence.