Several sites in east London suspected to be hosting crypto ATMs without the approval of the Financial Conduct Authority (FCA) were inspected by the agency.
In a joint operation with the Met Police, the FCA used its enforcement powers to visit the sites, but no arrests were made.
Crypto ATMs let people buy or convert money into cryptoassets, the FCA said.
No operators of such machines are registered with the FCA, which they must be in order to operate legally. The financial regulator labels crypto products as "high risk" and says users can lose all the money invested in these assets.
Read More: Government promises crypto regulation to make sector safer for retail investors
Mark Steward, executive director of enforcement and market oversight at the FCA, said: “This operation sends a clear message that we will continue to identify and disrupt unregistered crypto businesses in the UK."
The FCA explained it is working in partnership with the National Economic Crime Centre to crackdown on unregulated crypto ATMs throughout the country.
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