Latest: Calls for Google and YouTube to follow Facebook's ban on foreign referendum ads

Latest: There are calls for other social media companies to follow Facebook's lead and ban referendum ads from other countries.

Update 4.17pm: There are calls for other social media companies to follow Facebook's lead and ban referendum ads from other countries.

The social media giant made the announcement today as they say they're committed to protecting the integrity of elections and referendums from "undue influence".