LONDON (AP) — Google is suspending all advertising connected to Ireland’s abortion referendum as part of moves to protect “election integrity,” the company announced Wednesday.

The internet giant said that starting Thursday, it would no longer display ads related to the May 25 vote on whether to repeal Ireland’s constitutional ban on most abortions.

Google said the move is part of its global efforts to protect election integrity, and it comes amid concerns about the role of online ads in swaying voters. The prohibition on ads connected to the Irish vote applies to both Google and YouTube, which the company owns.

The online search leader, which is based in Mountain View, California, declined to say how much advertising revenue it was giving up because of the decision.

Google’s statement followed Facebook’s decision Tuesday to ban foreign advertisements around the abortion referendum, which has drawn worries about the influence of North American groups.

Ireland Sets Referendum Date as Hard Left Seeks to Repeal Unborn Right to Life https://t.co/CkbJ6nu8DI — Breitbart London (@BreitbartLondon) January 30, 2018

The role of online ads in elections is under scrutiny after revelations that political consultancy Britain-based Cambridge Analytica harvested Facebook users’ data to micro-target political ads to select groups during the 2016 U.S. presidential race.

Both Google and Facebook are working on measures to improve transparency ahead of November’s U.S. midterm elections, including tools to show the home country of advertisers.

Ireland bars political donations from abroad, but the law has not been applied to social media advertising. Anti-abortion groups based in the United States are among the organizations that have bought online ads in Ireland during the referendum campaign.

Largely Catholic Ireland has Europe’s strictest restrictions on abortion, which is legal only when a woman’s life is in danger. Several thousand Irish women travel each year to get abortions in neighboring Britain.

Voters are being asked whether they want to retain the constitutional ban or repeal it and make parliament responsible for creating abortion laws.