procedure for applying for U.S. citizenship

From p 34 of the Guide to Naturalization, "What if I live overseas? If you are overseas and filing Form N-400, you should send your application to the Service Center that serves the USCIS office where you want to be interviewed. For example, if you want to be interviewed at the Honolulu office, you should send your application to the California Service Center." The Guide is free at http://www.uscis.gov/natzguide .

US Embassies are staffed mostly by Department of State's personnel. USCIS is in a different department.

If you are overseas, you should check that you meet the "physical presence" and "continuous residence" tests. The Guide has information about naturalization applicable to most applicants.