It follows news that Hazem Abu Ismail may be barred from the poll because one of his parents held dual nationality.
Egypt’s electoral commission has said Hazem Abu Ismail’s late mother became a naturalized US citizen in October 2006.
But his supporters are calling on President Barack Obama to support their claim that the immigration paperwork is fraudulent.
Many of the postings are in Arabic, but one comment – posted by several users – said in English: “His mother was a scholar in America, she got American Green Card, but American Authorities are trying to fraud that she was an American citizen.”
Another user asked: “If the US administration has official documents, why not display them?”
Egypt’s presidential election rules say that all candidates must have been born in Egypt to Egyptian parents who have never held citizenship of another country, are not dual nationals, and are not married to a foreigner.
The head of the Higher Presidential Election Commission (HPEC), Hatem Bajatu, said on Thursday that it had received information that Hazem Abu Ismail’s mother had “used an American passport for travel to and from Egypt” before her death and that it would notify the Salafist preacher.
Hazem Abu Ismail – who is running on an ultra-conservative, nationalist and anti-foreign intervention platform – subsequently told his supporters that the allegations were a “plot” against him.
He said he had documents to prove his case and had hired American lawyers to help him.
The HPEC has said candidacy papers would be examined later this week, after which those who did not meet the requirements would be informed and allowed to appeal.
A final list of eligible candidates will be announced on 26 April.
The White House has not commented on the matter, but tens of thousands of angry messages from Hazem Abu Ismail’s supporters have been added to President Obama’s re-election campaign Facebook page.
They are attached to unrelated timeline updates posted in the president’s name including a video of the popstar Janelle Monae – a Barack Obama supporter – and a music playlist for his supporters.
The sheer number of posts are – at least temporarily – preventing the Facebook “Wall” being used as a forum to generate support for Barack Obama ahead of the US presidential vote on 6 November.
The Next Web news site notes that this is not the first time that one of the president’s social media profiles has been “flooded with comments from another country”.
It says Chinese citizens began posting comments to his Google+ page after the network was unblocked in China in February.
This has continued ever since, with some recent posts attracting roughly as many Chinese language comments as English ones.
It prompted one user to write: “Dear Chinese mainlanders spammers. Please respect the President of the United States of America and quit spamming his post!”
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