As used in this part:

Alien enemy means any person who is a native, citizen, subject or denizen of any country, state or sovereignty with which the United States is at war, for as long as the United States remains at war, as determined by proclamation of the President or resolution of Congress.

Denizen includes, but is not limited to, any person who has been admitted to residence and is entitled to certain rights in a country other than the one of the person's nationality. A person holding a status in another country equivalent to that of a lawful permanent resident in the United States would be considered to be a denizen.

An alien enemy may be naturalized as a citizen of the United States under section 331 of the Act if:

(a) The alien's application for naturalization is pending at the beginning of the state of war, or the Service has granted the alien an exception from the classification as an alien enemy after conducting an investigation in accordance with § 331.3;

(b) The alien's loyalty to the United States is fully established upon investigation by the Service in accordance with § 331.3; and

(c) The alien is otherwise entitled to admission to citizenship.

The Service shall conduct a full investigation of any alien enemy whose application for naturalization is pending upon declaration of war or at any time thereafter. This investigation may take place either prior to or after the examination on the application. This investigation shall encompass, but not be limited to, the applicant's loyalty to the United States and attachment to the country, state, or sovereignty with which the United States is at war.

(a) Upon determining that an applicant for naturalization is an alien enemy, the Service shall notify the applicant in writing of its determination. Upon service of this notice to the applicant, the provisions of section 336(b) of the Act will no longer apply to such applicant, until that applicant is no longer classifiable as an alien enemy.

(b) Upon completion of the investigation described in § 331.3, if the Service concludes that the applicant's loyalty and attachment to the United States have been fully established, the application may be granted.