PARIS (Reuters) -Europe's securities regulator warned crypto companies on Friday not to mislead customers about the extent to which their products are regulated - the latest sign of European authorities trying to limit crypto-related risks.

The European Union's crypto regulation, MiCA, includes various measures to protect investors, such as rules around how client assets are safeguarded and requirements for handling complaints, the European Securities and Markets Authority (ESMA) said in a statement.

But the practice of crypto asset service providers (CASPs) offering both regulated and unregulated products through the same platform "gives rise to investor protection risks", ESMA said, because customers might not be aware which products do not come with MiCA's protections.

"Some CASPs may even use their regulated status under MiCA as a marketing argument and encourage confusion between regulated and unregulated products and services," ESMA said.

ESMA said that crypto companies should not use their regulatory status as a "promotional tool" or imply that crypto products and services are regulated if they actually fall outside the scope of the EU's rules.

Regulators around the world have long been concerned about the risks faced by crypto investors. The collapse of various crypto platforms, including FTX, in 2022, left millions of investors out of pocket.

Under the EU's new crypto rules, companies offering crypto services must obtain a CASP licence from a national regulator, which can then be used as a passport to operate across the bloc.

ESMA also on Friday issued guidelines about the level of knowledge and competence staff need to have in order to assess crypto companies.

ESMA's statements come a day after it published a peer review into Malta's licence-granting process, which found that Malta's Financial Services Authority was not thorough enough in assessing the risk of one particular unnamed crypto company.

The review found that while the Maltese regulator had enough expertise and resources to authorise and supervise crypto companies, its authorisation process only "partially" met expectations.

The Maltese regulator said in a statement on Thursday that it was proud of its role as an "early adopter" of digital asset regulation and did not directly address ESMA's criticisms.

Some regulators had raised concerns in closed-door meetings about the speed with which crypto licences were being granted by some EU member states, Reuters has previously reported.