The top securities regulator in Massachusetts told CNBC yesterday that the bitcoin market is "entirely speculation."

"It doesn't pass the smell test," said Secretary of the Commonwealth William Galvin, whose responsibilities include overseeing the state's securities division. He warned:

Galvin's comments are the latest from U.S. regulators that warn investors about risks associated with cryptocurrencies, following the Securities Exchange Commission and the Financial Industry Regulatory Authority earlier this month.

Yet, it wasn't Galvin's first comment on the bitcoin market. Earlier this month, Galvin issued a press release cautioning against "bitcoin mania," while saying he is not coordinating with other state regulators on the issue at the moment.

The release listed seven points for investors to consider before buying bitcoin, including checking fees on exchanges, the inability to recover stolen funds and the wild fluctuations in price.

The federal government has also been cautioning investors about the cryptocurrency's historic rise. Galvin said, "we all seem to agree that this is a problem," and also extended his concerns to issues around other activities such as initial coin offerings.

"We believe they (ICO) certainly qualify as securities," Gavin said, adding "This is clearly an area with potentials for fraud. And we are very concerned about that."

Massachusetts State House image via Shutterstock.