Russian authorities' opposition to virtual currencies has been underlined after a presidential adviser referred to bitcoin as an internet joke and a virus and urged that it be outlawed.

Speaking to a local news agency, Presidential Adviser on the Internet, German Klimenko, also claimed that cryptocurrencies, in addition to being a "virus going straight into the head", are illegal in all countries in the world and that any idea that states otherwise is "but a mere fiction".

Bitcoin is not currently banned in Russia, though neither is it a legal currency. And despite an apparent backtracking on an outright ban in 2015, the Russian finance ministry is keen to push through new legislation later this year that will ban any bitcoin-based monetary activity and make it punishable with up to seven years in jail.

Russia is not alone in its opposition to bitcoin. A report by The Vanbex Group, Outlawing Bitcoin, Matter of Control, cites that Bolivia, Ecuador, Iceland, Kyrgyzstan and Vietnam are all seeking some level of ban while China is planning to issue its own centrally-issued virtual currency.