Update Jan. 26, 3:00 pm UTC: Coincheck has reported the likely inappropriate transfer of $532 mln worth of NEM to the Financial Services Agency and the Police, according to Nikkei.

Update Jan. 26, 2:00 pm UTC: NEM Foundation president Lon Wong has appeared to confirm Coincheck was hacked, calling the stolen funds "the biggest theft in the history of the world."

Japanese cryptocurrency exchange Coincheck has suspended all withdrawals as a Ripple payment worth $123mln left its wallet Friday, Jan. 26.

In what appears to be a problem tied to its support of altcoin NEM, Coincheck, which is among Japan’s largest exchanges, suddenly froze NEM deposits Friday.

An accompanying blog post stated:

“Depositing NEM on Coincheck is currently being restricted. Deposits made to your account will not be reflected in your balance, and we advise all users to refrain from making deposits until the restriction has been lifted.”

The restriction then spread to NEM sales and purchases, followed by withdrawals, before the exchange subsequently stopped all currency withdrawals, both crypto and fiat.

“All withdrawals from the platform are currently restricted, including JPY. Thank you for your understanding. We are doing our utmost to resume normal operations as soon as possible,” the most recent update to the blog post reads.

Since operations began to shut down, Coincheck’s wallet has shifted a one-off sum of 101,265,057 XRP, worth approximately $123.5 mln. Unconfirmed reports to Cointelegraph additionally allege $600 mln of NEM has left the exchange.

On both English and Japanese social media, Coincheck promised users it would provide full details in due course, while in the meantime apologizing for the abrupt cut to services.

Notably, Coincheck is not registered with Japan’s Financial Services Agency - a regulator responsible for overseeing exchanges in the country - unlike several other prominent cryptocurrency exchanges, such as bitFlyer and Quoine.

Reports have also surfaced of Japanese media starting to gather at Coinchek’s headquarters.