ZURICH (Reuters) - Swiss prosecutors on Thursday confirmed they were checking whether "questionable payments" to an ex-Mongolian finance minister were linked to Rio Tinto Oyu Tolgoi mining project, adding the Anglo-Australian mining company was "not an accused".

Reuters reported last week that the Office of the Attorney General (OAG) was examining whether Rio made illicit payments potentially linked to the copper and gold mine, part of the OAG's investigation into a seized Swiss bank account used in 2008 to transfer $10 million to Mongolia's former finance minister, Bayartsogt Sangajav.

Bayartsogt, who has denied wrongdoing, signed the investment deal which granted 66 percent of the giant Gobi desert property to Robert Friedland's Ivanhoe Mines, now known as Turquoise Hill Resources, and majority owned by Rio Tinto. Mongolia owns the rest.

"According to the current state of the investigation, Rio Tinto is not an accused," the OAG said in an e-mail to Reuters on Thursday.

"However, inquiries are being made as to whether the questionable payments to a former Mongolian finance minister were factually related to the Oyu Tolgoi mining project or to other mining projects in Mongolia."

Rio Tinto declined to comment.

Via its Swiss lawyers, Rio Tinto this week inquired about the OAG probe. They were told that "currently, the investigation is directed neither against your client nor against any of your client's employees," according to a letter from the OAG obtained by Reuters.

The Mongolian government requested Swiss legal assistance in the case in 2017.

Discussing the origins of the $10 million in Mongolia's capital Ulaanbaatar last week, Bayartsogt said the payment was not connected to Oyu Tolgoi, saying it was transferred to him by an investor to support a business he had established.

He declined to name the investor.

Swiss prosecutors seized two accounts containing about $1.85 million at a Swiss bank in 2016. Switzerland's highest court this month rejected the unidentified account holder's bid to unblock them.

Mongolia's anti-corruption authority has told Reuters that it is investigating a number of cases involving Bayartsogt.

The agency is also investigating the country's 2009 investment pact with Rio Tinto which kickstarted the massive project.

(Reporting by John Miller; editing by Jason Neely)

By John Miller

Stocks treated in this article : Rio Tinto Limited, Rio Tinto