Twitter labelled the post for potentially discouraging voters from heading to the polls. Facebook though, did not put any warning label on an identical post.
Twitter has flagged a Donald Trump post about the forthcoming presidential election for violating its rules.
The US President said, without any proof, that mail drop boxes would be a "voter security disaster".
He also suggested they would not be "COVID sanitised".
The platform said the tweet had violated its civic integrity policy by "making misleading health claims that could potentially dissuade people from participation in voting".
The policy - or rules - are aimed at stopping people using Twitter for the "purpose of manipulating or interfering in elections or other civic processes".
By flagging Trump's post, Twitter, in a bid to slow its spread, removed the ability to like, comment underneath or share it with a message,
Misrepresentation with regards to methods of voting is also against Facebook's policies.
Facebook did not respond to a request for comment on why they did not take similar action with regard to the identical post published on their platform.
Facebook added a label encouraging users to go to their new Voting Information Centre which was launched on August 13. The centre aims to provide accurate and up-to-date information on the elections and gives information on how to vote.
Such labels, however, are not an indication that a post has breached their guidelines.
In a press statement at the time, Facebook's VP of Product and Social Impact, Naomi Gleit, had said that the labels would give "easy access to the latest official election information".
This is not the first time Twitter labelled posts published by the US President. In May, the platform first labelled posts published by President Trump for spreading misinformation about mail-in voting.