22 CFR § 92.86
Consular responsibility for serving subpoenas
November 19, 2020
When directed by the Department of State, officers of the Foreign Service will serve a subpoena issued by a court of the United States on a national or resident of the United States who is in a foreign country unless such action is prohibited by the law of the foreign country.
[32 FR 11776, Aug. 16, 1967]