The U.S. securities watchdog has halted trading in two cryptocurrency-related products because of confusion over the nature of the financial products.

The securities, Bitcoin Tracker One and Ether Tracker One, were slapped with a suspension notice by the Securities and Exchange Commission (SEC) on its website.

The regulator said that broker-dealer application materials and trading websites characterized the products as exchange-traded funds (ETFs) - listed funds that track a basket of assets.

Instead, the securities are "non-equity linked certificates," the SEC said, citing the products' issuer. The SEC ordered trading to be halted until September 20.

"It appears … that there is a lack of current, consistent and accurate information concerning Bitcoin Tracker One (Ticker Symbol: CXBTF) and Ether Tracker One (Ticker Symbol: CETHF), issued by XBT Provider AB (publ), a Swedish company headquartered in Stockholm, resulting in confusion amongst market participants regarding these financial instruments."

It added: "The Commission is of the opinion that the public interest and the protection of investors require a suspension of trading in the securities of the above quoted company."