The U.K.'s financial regulator has issued a warning to investors over an unregistered brokerage firm that appears to be offering cryptocurrency-related derivatives in the country.

In a statement Thursday, the Financial Conduct Authority took aim at a firm called Olsson Capital, which, according to the regulator, is based in Sofia, Bulgaria.

"This firm is not authorized by us and is targeting people in the U.K. Based upon information we hold, we believe it is carrying on regulated activities which require authorization," the agency said.

While the firm’s website is currently not accessible, information from Scambroker, a website that scrutinizes securities brokers and dealers, shows that the firm has been handling cryptocurrency trading services and is not registered with the FCA as a licensed broker.

The website further indicates that services available on Olsson Capital include contract for difference (CFD) trading on a variety of cryptocurrencies, including bitcoin, XRP, dash, ethereum, monero and litecoin. Further, investors need to deposit at least around $250 in order to open an account on the platform, ScamBroker states.

While Olsson Capital has not responded to email enquires from CoinDesk, comments on Scambroker from several investors have claimed that requests for withdrawals have not been proceeded even days after requests.

The notice comes as a continuation of the FCA's efforts to caution the public regarding trading in cryptocurrency-related derivatives, as such activities fall under the jurisdiction of the agency.

As reported by CoinDesk, the regulator issued a warning to the public in November 2017, specifically regarding the risk associated with cryptocurrency CFDs.

And, earlier last year, a high level official at the FCA also stated that the public must "exercise a degree of caution" with such products.

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