TMEP § 906.01
In addition to the United States, several countries recognize use of the symbol ® to designate registration. When a foreign applicant’s use of the symbol on the specimens is based on a registration in a foreign country, the use is appropriate.
The following foreign countries use the ® symbol to indicate that a mark is registered in their country:
In addition, owners of European Union trademarks use the ® symbol to indicate that their mark is registered with the European Union Intellectual Property Office.