Photo/Illutration DMM Bitcoin’s website announcing the unauthorized outflow of bitcoin

Japanese cryptocurrency exchange DMM Bitcoin said it had lost approximately 48.2 billion yen ($306 million) worth of Bitcoin due to an "unauthorized leak."

The company vowed to guarantee the full amount in Bitcoin entrusted to it by its customers.

DMM said it detected an unauthorized outflow of Bitcoins around 1:26 p.m. on May 31. For security reasons, the company has restricted some of its services.

The company handles 40 or so types of crypto assets, including Bitcoin.

In 2018, Tokyo-based crypto currency exchange company Coincheck reported a leak of approximately 58 billion yen through unauthorized access.