Twitter announced Monday it will ban advertising for cryptocurrencies, joining advertising giants Google and Facebook in a wider crackdown that aims to protect investors from fraud.

"We are committed to ensuring the safety of the Twitter community. As such, we have added a new policy for Twitter Ads relating to cryptocurrency," a Twitter spokesperson told CNBC Monday. "Under this new policy, the advertisement of Initial Coin Offerings (ICOs) and token sales will be prohibited globally."

Possibilities of a ban were reported last week. Bitcoin prices fell near the $7,000 level following that news, then recovered $700 in less than three hours the same day.

Twitter's announcement Monday echoes other tech giants' policy changes.

Google, the world's largest online ad provider, announced an update to its financial services policy earlier in March that will restrict advertising for "cryptocurrencies and related content" starting in June.