"Clearly, this is a matter of deep concern and we are working hard to rectify the matter in the coming days", the announcement said.
Skraba told Reuters NiceHash was cooperating with local authorities, but declined to provide further information.
The company did not respond to requests for comment.
"Importantly, our payment system was compromised and the contents of the NiceHash Bitcoin wallet have been stolen". But some of the company's customers speculated that around 4,736 bitcoin total were stolen - worth over US$63 million as of Wednesday afternoon. Wallet is a nickname for an online account.
NiceHash offers a cryptocurrency mining service. Nicehash offers a server where individuals offer computing capacity to bitcoin miners to mine bitcoins via complicated math equations in order to create blockchains, the basis for cryptocurrency. Users can also buy computer processing power from other NiceHash users.
The Futures Industry Association, which represents Wall Street's biggest banks and clearing houses, sent a letter to the Commodities Futures Trading Commission, saying that as the guarantors of customers trades, they should have been consulted before trading in bitcoin futures was approved. But some users have chosen instead to keep their earnings on NiceHash.
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The surge in the price and the hack of NiceHash occurred just as the trading community prepares for bitcoin to start trading on two established US exchanges. Others said their balances on the website went down to zero.
The marketplace is among the largest in the world and has raised serious alarms for security threats for online companies.
As bitcoin price fluctuates wildly, other cryptocurrencies like ethereum and litecoin are falling.
Another major hack occurred just last month on Parity, a digital wallet popular with startups collecting millions of dollars in fundraising.
Tech-savvy users called "miners" use their computers to make complex calculations that verify transactions in bitcoins.