LONDON (Reuters) - Twitter Inc (TWTR.N) will start banning cryptocurrency advertising from Tuesday, joining Facebook and Google in a clampdown that seeks to avoid giving publicity to potential fraud or large investor losses.

The prohibition will cover advertising of initial coin offerings (ICOs) - crowdfunding used to raise cash by creating new coins - as well as token sales, the San Francisco-based firm told Reuters on Monday.

The new policy, which will be rolled out over the next 30 days, will also ban ads by cryptocurrency exchanges and cryptocurrency wallet services, unless they are public companies listed on certain major stock markets.

For Japan, these will be limited to crypto exchanges regulated by its national financial regulator, Twitter said.