FILE PHOTO - High-end graphic cards are installed in a cryptocurrency mining computer at a computer mall in Hong Kong, China January 29, 2018. REUTERS/Bobby Yip/File Photo

NEW YORK (Reuters) - The U.S. Securities and Exchange Commission said on Sunday it was immediately suspending trading in two investment products that track cryptocurrencies, citing confusion in the markets over whether the products are exchange-traded funds (ETFs).

The SEC said in a statement that trading in Bitcoin Tracker One and Ether Tracker One would be halted in the United States until at least Sept. 20.

The products promise to track the price of the cryptocurrencies, less fees. They are both listed on a Nasdaq Inc NDAQ.O exchange in Stockholm, but trade "over the counter" in transactions that occur off exchanges within the United States.

“It appears ... that there is a lack of current, consistent and accurate information,” the SEC said in a notice posted on its website. “Application materials submitted to enable the offer and sale of these financial products in the United States, as well as certain trading websites, characterize them as ‘Exchange Traded Funds.’”

The issuer of Bitcoin Tracker One and Ether Tracker One, XBT Provider AB SE0010296574.ST and its parent company, did not immediately respond to emailed requests for comment. Nasdaq declined to comment.

The SEC has taken a strict stance against letting ETFs tracking bitcoin and other cryptocurrencies come to market.

But investment firms have been pushing other types of investments that attempt to make it as easy to trade cryptocurrencies as a regular stock.

Those products are sometimes called ETFs, but that term generally refers to a different and often more stringently regulated product. Some industry experts, including the largest ETF provider BlackRock Inc BLK.N, have called for regulators to standardize the terms used to describe ETFs and other kinds of investment products.

Virtual currency, including bitcoin and ether, can be used to move money around the world quickly and with relative anonymity, without the need for a central authority, such as a bank or government. A fund holding the currency could attract more investors and push its price higher.