The price of Bitcoin fluctuated amid concerns that South Korea will shut down exchanges.<br />The top cryptocurrencies are all trading lower across the board.<br />Bitcoin is now trading at $13,891, after regaining loses from a week before.<br />Three of the other top five digital currencies also suffered loses during afternoon trading.<br />The concern stems from the crypto-exchanges Bittrex, Bitfinex, and CEX.io, who are struggling to scale-up with user-demand.<br />Those exchanges, which are some of Bitcoin's biggest, stopped registering new users as they upgrade their backend systems. <br />
