A Coin Trader employee uses a smartphone to demonstrates how to purchase bitcoins from an automated teller machine in Tokyo.

Bitcoin prices fell roughly 9 percent Friday after Japan's financial regulator ordered several cryptocurrency exchanges to improve their practices against money laundering.

The digital currency fell to $6,081, breaking below $6,400 for the first time in about a week and reaching its lowest level since February 6, according to CoinDesk.

The order from Japan's Financial Services Agency led bitFlyer — the country's largest crypto exchange — to suspend the creation of new accounts while it makes improvements, especially in its measures to stop money laundering and terrorist financing.

"Our management and all employees are united in our understanding of how serious these issues are, as well as how serious we are in responding to them going forward," bitFlyer said in a statement on its website.

Bitcoin's Friday performance

Source: CoinDesk

"In order to maximize our efforts towards building a suitable service and improving on the issues identified, we have temporarily suspended account creation for new customers of our own volition," bitFlyer said.

The agency gave the same order to five other exchanges after finding weaknesses in their controls against money laundering.

"In the long term, it builds a better ecosystem and makes sure this is a legitimate asset class," said Brian Kelly, founder and CEO of BKCM. "This is part of making sure exchanges are up to snuff."

In the short run, Kelly pointed out, it reduces the flow of new capital to the largest exchange in the largest market for bitcoin trading. Bitcoin trading in Japanese yen makes up more than 60 percent of the digital currency's daily volume, according to data from market analysis site CryptoCompare.