The Overseas Security Advisory Council (OSAC) separately announced that the US Embassy in Oman will be open during Ramadhan for American Citizens Services by appointment only, between 11am and 12 noon on Sundays, Mondays, Wednesdays, and Thursdays, and between 8am and 10am on Tuesdays. Appointments are available online and may be accessed here.
When visiting the embassy, the OSAC states that American citizens should bring two forms of government-issued identification with photographs, as one must be left with the security guards while inside the building. Non-immigrant visa services during Ramadhan are available from 8am to 10:30am on Sundays, Mondays, Wednesdays, and Thursdays.