A campaign launched by the Green Party candidate Jill Stein to recount key states in the US election has reached its initial funding target of $2.5 million in just a matter of hours.

The money will allow Ms Stein to review the results in Wisconsin, Michigin and Pennsylvania, where concerns have been raised over irregularities with electronic voting results.

Each of the states voted narrowly in favour of Donald Trump (though the final Michigin count is still to be confirmed), and carry enough electoral college votes between them to change the result of the election if all were redeclared for Hillary Clinton.

A team of computer scientists said they had evidence to show Ms Clinton's vote was 7 per cent down on average in Wisconsin counties where electronic voting machines are used.

They speculated that correcting for the error would give the Democratic candidate an additional 30,000 votes. She lost the state as a whole by just 27,000.

But 538 pollster Nate Silver has dismissed this as evidence of wrongdoing, suggesting the difference can be accounted for by the demographics of the counties in question.

In a post alongside the online fundraiser, Ms Stein's team said they were raising money "to demand recounts in these three states where the data suggests a significant need to verify machine-counted vote totals".

“These concerns need to be investigated before the 2016 presidential election is certified,” she said. “We deserve elections we can trust.”

The team behind the original blog post raising concerns, including voting rights lawyer John Bonifaz and J Alex Halderman, director of the University of Michigan's center for computer security and society, said they had been in contact with the Clinton campaign team about their findings.

But there was also understood to be significant pressure on Ms Clinton to publicly accept the election result, after she criticised Mr Trump for not committing to do so during the campaign.

Ms Stein said she was not acting in support of any single candidate, but "to shine a light on just how untrustworthy the U.S. election system is".

Her team said she needed the $2.5 million target before the Friday deadline for requesting a recount in Wisconsin, while Pennsylvania and Michigan have deadlines of Monday and Wednesday 30 November respectively.

Meanwhile, Ms Clinton's lead over Mr Trump in the popular vote continues to grow, reaching above more than 2 million on Wednesday.