FRANKFURT No one is a prophet in their own land, including European Central Bank President Christine Lagarde, who admitted on Friday that her son lost "almost all" of his investments in crypto assets, despite copious warnings.

Lagarde has long railed against cryptocurrencies, calling them speculative, worthless and a tool often used by criminals for illicit activity.

"He ignored me royally, which is his privilege," Lagarde told a town hall with students in Frankfurt. "And he lost almost all the money that he had invested."

"It wasn't a lot but he lost it all, he lost about 60% of it," Lagarde added. "So when I then had another talk with him about it, he reluctantly accepted that I was right."

The ECB chief has two sons in their mid-30s but did not say which one she was referring to.

The ECB has called for global regulation of crypto assets both to protect consumers who are unaware of the risk and to close a loophole that can be used to channel funding to terrorists or lets criminals launder cash.

Worries that privately issued currencies could displace government money were among the reasons the ECB launched its own digital euro project, but the bank is still years away from issuing any digital money.

Last month the bank started the "preparation phase" for the digital euro but said it would need another two years before it was in a position to decide whether to roll it out or not.

"I have, as you can tell, a very low opinion of cryptos," Lagarde said. "People are free to invest their money where they want, people are free to speculate as much as they want, (but) people should not be free to participate in criminally sanctioned trade and businesses."

(Reporting by Balazs Koranyi; Editing by Susan Fenton)