Just as bitcoin soared yet again to a new high, passing $17,000, bitcoin mining company NiceHash has reported that it has suspended operations after evidence of a security breach.

Bitcoins, which are digital currency, are just one of several types of digital tokens used for payment to those who trade in cryptocurrencies.

In a statement on its website, NiceHash said, “Importantly, our payment system was compromised and the contents of the NiceHash Bitcoin wallet have been stolen. We are working to verify the precise number of BTC taken.”

According to Chicago Tribune, Coindesk, a research company, said that a wallet address referred to by NiceHash users indicates that close to 4,700 bitcoins had been taken. That could put the size of the cyber heist at about $70 million worth of bitcoin.

Read more at Chicago Tribune.