The Coincheck exchange has lost 58 billion yen ($530 million) in cryptocurrency because of hacking.
The Coincheck exchange said on its website Friday that it had halted sales and withdrawals of the currency, which is called NEM. It later added that it had restricted dealings in most other cryptocurrencies too.
At a Friday night news conference, Coincheck President Koichiro Wada bowed and apologized. He said the company may seek financial assistance.japanese TV footage showed a small group of customers standing outside the company's head office.