Several cryptocurrency exchanges had accounts in Bulgarian banks. You can imagine the surprise and frustration, when they found their accounts terminated.
More than that, transfers from and to international exchanges are blocked, as well.
Still, cryptocurrency exchanges are forced to deal with banks for exchanges, but the transfers are much riskier when made in cryptocurrency. Moreover, they are irreversible. So, Bulgarian banks decided to eliminate the risks, even if by force.
It is worth mentioning that government did not impose any sanctions on cryptocurrencies neither had any additional regulations issued. The blocking of cryptocurrency exchanges accounts looks like a coordinated action and was taken by all major banks, supposedly, in the effort to lower risks connected with cryptocurrency transfers.