The US Securities and Exchange Commission has halted a multi-million dollar digital token sale by California-based restaurant review app firm Munchee.
The US regulator also warned consumers of the dangers of investing in crypto-currencies issued by firms.
SEC chairman Jay Clayton said there were substantially more opportunities for fraud from initial coin offerings.
It's the latest in a string of warnings from global regulators.
Initial coin offerings (ICOs) let startups quickly raise capital by issuing virtual tokens to investors, usually in exchange for more established crypto-currencies such as Bitcoin or Ethereum.
These tokens typically use blockchain, which uses cryptography to record transactions which can then be authenticated.
US identity verification firm Civic raised $33m (£26m) this year, while blockchain technology firms Bancor and Tezos raised more than $350m. The value of Bancor tokens have dropped by about half since June, according to the firm's website.
"We will continue to scrutinise the market vigilantly for improper offerings that seek to sell securities to the general public without the required registration or exemption," said Stephanie Avakian, co-director of the SEC's enforcement division.
Munchee had been seeking to raise $15m to create an "ecosystem" where Munchee and others could buy and sell goods and services using the tokens.
But the firm had said investors could expect to make a return on their investment, which would make the tokens a security requiring SEC registration.
The SEC halted the sale of the tokens on 1 November, the day after they went on sale, the regulator said in a cease and desist order.
SEC chairman Jay Clayton warned consumers that "there is substantially less investor protection than in our traditional securities markets, with correspondingly greater opportunities for fraud and manipulation" with initial coin offerings.
Regulators around the world are becoming increasingly concerned with the popularity of ICOs.
In the UK, the Financial Conduct Authority said in September that investors could lose their entire stake in high-risk digital token investments.
Earlier this year China banned initial coin offerings, calling them "illegal fundraising".