New York Attorney General Letitia James on Monday warned Americans they could face crippling losses from unprotected trading in cryptocurrencies.

James’ office shut down digital currency trading platform Bitfinex last week and fined its operators $18.5 million for defrauding investors over some $850 million of losses.

​James’ remarks came as Bitcoin, the number one digital currency, fell some 10 percent in value over the weekend before recovering in Monday’s trade. Cryptocurrencies, in general, are volatile because they have no intrinsic value and are often associated with funding for illicit activity. Bitcoin, for instance, rallied from below $10,800 in September to record highs above $58,000 last month.

Separately, the Justice Department said last week it had charged a 45-year-old Serbian residing in New York with hatching a bogus cryptocurrency scheme using two fraudulent online investment platforms to solicit some $7 million from unsuspecting Americans.