The stored details did not concern terrorism, which is a requirement in order for the FRA to save the information.
A anonymous person has tipped off the Swedish Data Inspection Board (Datainspektionen). The person questioned whether the FRA has the legal basis for its operations and for saving the information, according to the board's director-general Göran Gräslund, speaking to the Swedish public radio news programme Ekot.
According to the anonymous tip the FRA has been bugging the telephone conversations between the Russians and contacts in Russia during the 1990s.
According to Ekot the conversations have concerned computer sales, contact with the Russian timber industry and a training project for unemployed specialists.
Swedish legislation allows only for the recording of information in connection with terrorism. In the cases in question security police have not had any interest in any of the people involved, according to the person who filed the report to the Data Inspection Board.
Gräslund said that it is too early to tell if the case constitutes the illegal misuse of computer information. The board has so far done little more than classify the investigation as top secret and has not made any decision over whether to pursue the case.
The report comes at a sensitive time for data protection in Sweden. On Tuesday the parliament will vote on new legislation which will allow the FRA to monitor more communications traffic, including satellite.
The government wants the surveillance law to cover cable communications such as internet, e-mail and fax.