Ivana Kottasová

(CNN Money) -- Facebook is banning foreign groups from buying advertisements related to Ireland's abortion referendum, the company announced Tuesday.

Under Irish law, foreign citizens and groups are not allowed to make donations to Irish campaign groups. However, foreigners were until Tuesday able to purchase Facebook ads directly targeting Irish voters.

"As part of our efforts to help protect the integrity of elections and referendums from undue influence, we will begin rejecting ads related to the referendum if they are being run by advertisers based outside of Ireland," Facebook said in a statement.

"We feel the spirit of this approach is also consistent with the Irish electoral law that prohibits campaigns from accepting foreign donations," it said.

The May 25 referendum will decide whether abortion should be legalized in Ireland. The country's abortion laws are among the strictest in the developed world.

Facebook says it has learned the lessons of Russian meddling in the 2016 US election, and is working on changes to make election campaigns more transparent.

The company will soon start requiring political advertisers to be residents in the country where the election is taking place. Ireland is the first country where Facebook has implemented the rule.

The Irish Transparent Referendum Initiative has identified several ads paid for by UK and US-based anti-abortion groups targeting users in Ireland ahead of the referendum.

The campaigners were pushing for Facebook and other social media companies to ban the practice, saying online and offline regulation should be the same.

Facebook has already stepped up efforts to tackle fake news ahead of the vote, rolling out a new tool in Ireland to give users more information about political advertisements and sponsored posts in their news feeds.

Users are now able to see all of the content originating from the Facebook account behind those posts, rather than just the ads or stories targeted at them.

This should also help them identify which posts are shared by friends, or their wider network, and which result from paid campaigning.