An official record or an entry therein, when admissible for any purpose, may be evidenced by an official publication thereof or by a copy attested by the officer having the legal custody of the record, or by a deputy, and accompanied with a certificate that such officer has the custody. If the office in which the record is kept is within the United States or within a territory or insular possession subject to the dominion of the United States, the certificate may be made by a judge of a court of record of the district or political subdivision in which the record is kept, authenticated by the seal of the court, or may be made by any public officer having a seal of office and having official duties in the district or political subdivision in which the record is kept, authenticated by the seal of his office. If the office in which the record is kept is in a foreign state or country, the certificate may be made by a secretary of embassy or legation, consul general, consul, vice consul, or consular agent or by officer in the foreign service of the United States stationed in the foreign state or country in which the record is kept, and authenticated by the seal of his office. A written statement signed by an officer having the custody of an official record or by his deputy that after diligent search no record or entry of a specified tenor is found to exist in the records of his office, accompanied by a certificate as above provided, is admissible as evidence that the records of this office contain no such record or entry. This section does not prevent the proof of official records or of entry or lack of entry therein or official notice thereof by a method authorized by any applicable statute or by the rules of evidence.