Alphabet Inc's Google will block election-related ads on its platforms after polls close in the U.S. election on Nov. 3, the company told advertisers in an email on Friday.

The email, seen by Reuters and first reported by Axios, said that "advertisers will not be able to run ads referencing candidates, the election, or its outcome, given that an unprecedented amount of votes will be counted after election day this year."

Experts warn that the election results could be delayed due to increased mail-in voting amid the coronavirus pandemic.

The email said the company would ban election ads, including those that mention state or federal office-holders, candidates, or political parties, as well as ads running on election-related search queries.

Social media companies have been facing growing pressure to police misinformation in political ads. Facebook Inc FB.O recently said it would stop accepting new political ads in the week before the election and would reject ads that seek to claim victory before the results of the election are declared.

A Google spokeswoman said the ban was expected to be in place for a minimum of a week but that it was not decided when the ban would be lifted. She said the company would consider factors such as the time taken for votes to be counted or whether there was civil unrest.

The ban forms part of Google's 'sensitive events' policy, she said. Google has blocked some ads relating to COVID-19 under the same policy, which seeks to prohibit content that potentially capitalizes on or lacks reasonable sensitivity towards events like public health emergencies or natural disasters.

The ban will apply to all ads on Google's ad-serving platforms, including its video-streaming service YouTube and Google Ads.

Twitter Inc banned political ads last year, while Google has previously limited the ways election advertisers can micro-target voters.

(Reporting by Ayanti Bera in Bengaluru and Elizabeth Culliford in Birmingham, England; Editing by Shailesh Kuber and Rosalba O'Brien) ((Ayanti.Bera@thomsonreuters.com; 646 223 8780 - 3401;))