The United States Tennis Association has apologised after a version of the German national anthem associated with the Nazi era was accidentally sung at a tournament in Hawaii.
The obsolete first verse, including the words "Germany, Germany above all else" was sung by a soloist at the Fed Cup.
The error left members of the German team and fans upset and angry.
The USTA extended "a sincere apology to the German Fed Cup team and fans for the outdated National Anthem".
"This mistake will not occur again," it said.
Germany's Andrea Petkovic and Alison Riske of the US were about to play their first-round tie when the anthem was heard.