Image copyright Reuters Image caption Petkovic was among the German team members outraged by the mistake

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The USTA extended "a sincere apology to the German Fed Cup team and fans for the outdated National Anthem".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.

"It was an absolute outrage and affront, the lowest," Petkovic said. "It was by some way the worst thing that's happened to me, especially in the Fed Cup."

Image copyright USTA

The song, the Deutschlandlied, became the official German anthem under the democratic Weimar Republic in the 1920s.

But after World War Two, the first, contentious verse was dropped and the Federal Republic adopted only the third verse beginning "Unity and justice and freedom".

The Fed Cup is the largest international team competition in women's tennis, and included 99 teams in 2015.

Petkovic lost to Riske, 7-6, 6-2.

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