They said Elfriede Lina Rinkel, 83, a native and citizen of Germany, served as a guard at the Ravensbruck concentration camp in Germany from June 1944 until the camp was abandoned in the closing weeks of the war.

A San Francisco woman has been sent back to Germany after admitting she took part in Nazi acts of persecution as a concentration camp guard of female prisoners during World War Two. [Reuters]

In a settlement agreement, Rinkel admitted she served as a guard and that she must be deported from the United States under a federal law that requires the removal of immigrants who participated in acts of Nazi-sponsored persecution.

She agreed to an immigration court order directing her removal to Germany, and returned to Germany earlier this month, the officials said.

Rinkel never told her husband -- a German Jew who fled to the United States during the Nazi regime -- that she was a concentration camp guard, the San Francisco Chronicle reported, quoting the woman's lawyer. The husband died in 2004.

"Concentration camp guards such as Elfriede Rinkel played a vital role in the Nazi regime's horrific mistreatment of innocent victims," Assistant Attorney General Alice Fisher said in a statement. "This case reflects the government's unwavering commitment to remove Nazi persecutors from this country."

Established in 1939, Ravensbruck was the only Nazi concentration camp operated exclusively for female prisoners.

A charging document filed in U.S. immigration court in San Francisco stated that Rinkel used a trained attack dog to carry out her duties.

At Ravensbruck, female guards with attack dogs forced the women inmates to march to slave labor sites each day, guarded them while they performed manual labor, and then marched them back to the camp, the officials said.

The charging document said Rinkel's activities at the camp assisted the Nazis in persecuting civilians, and that her removal from the United States was required by law.

Rinkel immigrated to the United States from Germany in 1959. She was accused of concealing her concentration camp service from U.S. immigration authorities when she applied for her entry visa.

The case was investigated by the Justice Department's Nazi-hunting Office of Special Investigations.

"Thousands of innocent women were brutalized and murdered at Ravensbruck through the active participation of Elfriede Rinkel and other guards, whose principal function was to prevent prisoners from escaping the abominable conditions inside the camp," said Eli Rosenbaum, the office director.