Facebook and Twitter have announced the decision to flag certain posts on United States election.

The U.S. presidential poll holds today. President Donald Trump and Democratic candidate, Joe Biden are in a tight race.

The social media giants will put labels on posts from candidates and campaigns that claim early victory.

The high number of mail-in ballots is likely to cause a delay in final results, Reuters reports.

From now until inauguration, Twitter will place notifications such as “official sources called this election differently”, or “official sources may not have called the race when this was tweeted” on some posts.

Accounts in America with over 100,000 followers and a high engagement may be labelled.

Twitter added that news outlets including ABC News, Associated Press, CNN, and Fox News would be considered as official sources for results.

In a statement, Facebook noted that labels will be placed if a candidate or a party declares premature victory.

The company said latest official results will be displayed in its Voting Information Centre.

Facebook will also monitor reports of voter suppression content, and remove any attempts to suppress participation or intimidate voters.