Facebook said Friday it's further tightening up requirements for European Union political advertising, in its latest efforts to prevent foreign interference and increase transparency ahead of bloc-wide voting in May.
The social media giant said it will require political advertisers to confirm they are located in an EU country. That's on top of a previously announced requirement that ad buyers must confirm their identities.
Ads that don't comply will be blocked starting in mid-April.
Silicon Valley tech companies are facing rising pressure from EU authorities to do more to prevent their platforms being used by outside groups to meddle in elections.
EU officials in January singled out Russia as a prime source of disinformation in Europe. Hundreds of millions of people are set to vote for more than 700 EU parliamentary lawmakers on May 23-26.
Facebook, which also owns Instagram and WhatsApp, will ask ad buyers to submit documents and will use technical checks to verify their identity and location.
"We recognise that some people can try and work around any system but we are confident this will be a real barrier for anyone thinking of using our ads to interfere in an election from outside of a country," Richard Allen, Facebook's vice president of global policy solutions, said in a blog post.
Facebook said earlier this year that EU political ads will carry "paid for by" disclaimers. Clicking the label will reveal more detailed information such as how much money was spent on the ad, how many people saw it, and their age, gender and location.
The ad transparency rules have already been rolled out in the U.S., Britain, Brazil, India, Ukraine and Israel. Facebook will expand them globally by the end of June. Twitter and Google have introduced similar political ad requirements.
Facebook is also making improvements to a database that stores ads for seven years, including widening access so that election regulators and watchdog groups can analyze political or issue ads.