2,144. A Kohein vs. a Yisroel

Hilchos Issurei Biah 12:2

The Biblical prohibition (in the previous halacha) only applies in the context of marriage. If one engages in promiscuous relations with a non-Jewish woman, he is given stripes for acting rebelliously by rabbinic enactment, as a preventive measure against marriage. If a Jewish man picks out a non-Jewish woman for purposes of promiscuity, he is liable for relations with a niddah, a female servant, a non-Jewish woman and a prostitute. If he didn’t select her for himself, but rather it happened spontaneously, he is only liable for relations with a non-Jewish woman. All of this is by rabbinic enactment.

Hilchos Issurei Biah 12:3

All of the above is only the case when the man is a Yisroel (an Israelite). If a kohein engages in relations with a non-Jewish woman, he is liable for lashes under Biblical law because of the prohibition against a kohein being intimate with a zonah, which applies to both to Jewish and non-Jewish women. (The word “zonah” is commonly used for a prostitute but it technically refers to a woman who has had relations that make her unable to marry a kohein.). A kohein only receives lashes for the sexual congress because he’s not able to betroth her.