People walk next to Forever 21 store at Jockey Plaza Mall in Lima, Peru, December 9, 2016. REUTERS/Mariana Bazo

(Reuters) - Fashion retailer Forever 21 said on Tuesday there had been unauthorized access to data from payment cards used at certain of its stores.

The company said the results were part of an investigation it started after it received a third-party report suggesting the unauthorized access.

The Los Angeles, California based company said the probe was focused on transactions made at its stores between March and October this year, and that since the investigation was ongoing, it could not give complete findings.

Forever 21 said only certain point of sale devices in certain stores were affected when the encryption on those devices was not operating.

The company, which operates more than 815 stores in 57 countries, did not say which of its stores were affected.