scientific embargo

Are US science journals not allowed to publish Iranian research?

I received an email from what seems to be a credible source saying that an Iranian working in the field of orthodontics submitted a paper to an American journal. The paper was refused solely on the grounds of the paper’s country of origin, Iran.

This is the email the Iranian orthodontist is claimed to have received (names have been removed by the source of information):

Dear Dr. XXXX

We have received your manuscript in our automated system. Unfortunately, our Federal Government does not allow us to process and edit manuscripts submitted from Iran.

I regret that the world situation results in our inability to communicate science as we would wish. I suggest that you submit your manuscript to a European journal or a journal located in some other country than ours.

Thank you for your interest in The XXXXX.

Sincerely,

XXXXX, DDS, MSD, PhD
Editor-in-Chief, The XXXX
Professor Emeritus
University of XXXXX
XXXXXX University

This is definitely worth looking into. Has the US government really issued warnings to scientific journals against publishing research by Iranian scientists? If so, why? When do political sanctions go too far? Is it smart to sanction science and scientific research?