American Green Party leader Jill Stein has raised more than $3m dollars to challenge the 2016 vote in key battleground states where security experts say it could have been manipulated.

Through a crowd-funding effort launched Wednesday (23 November) Stein has already gathered enough cash to fund a recount in Wisconsin. That will cost $1.1m and her fund aims for a total of $4.5m to carry out recounts in Michigan and Pennsylvania too.

Wisconsin officials are already preparing to begin the process, according to Elections Commission director Michael Haas. In the state unofficial numbers show President-elect Donald Trump narrowly beat out his Democratic rival Hillary Clinton by 22,525 votes. Trump took Pennsylvania by 70,010 votes and Michigan by 10,704.

"After a divisive and painful presidential race, reported hacks into voter and party databases and individual email accounts are causing many American to wonder if our election results are reliable," said Jill Stein in a statement Tuesday (22 November). "These concerns need to be investigated before the 2016 presidential election is certified. We deserve elections we can trust."

Stein's comments came after a computer expert and lawyer raised concerns about the vote early this week. Cybersecurity expert J Alex Halderman, director of the University of Michigan Center for Computer Security and Society, and constitutional law and voting rights lawyer John Bonifaz said they believe they have found evidence indicating the vote in the three states could have been manipulated or hacked.

In a blog post, Halderman cited a 2014 attempt by Russia to hack the Ukrainian election. Hacks over the summer of the Democratic party and Clinton campaign have been attributed to Russia at the highest levels on the US government.

Using a statistical analysis the two experts found that in Wisconsin Clinton got 7% fewer votes in counties that used electronic voting machines compared to others where paper votes and scanners were used. They don't claim that this is proves anything, but rather that it's a pattern that needs investigation, they said.

Clinton is not backing the recount, but her campaign chair John Podesta heard out the two experts in a conference call. Clinton's share of the popular vote passed more than 2 million ballots on Wednesday (23 November), making her the first candidate in US history to lose after gaining that much of the vote.

To have the result of the election overturned, however, would require Clinton to gain more of the Electoral College vote than Trump. He currently holds 290 of those votes and Clinton has 232. Exactly 10 Electoral College votes belong to Wisconsin, 20 to Pennsylvania, and 16 in Michigan.

Yet no credible evidence of manipulation has emerged so far, said Haas at the Elections Commission. The timings to call for a recount in the other states are coming up fast. Pennsylvania needs notification by Monday (28 November) and Michigan by 30 November.

"Some of the machines used in Wisconsin, have been banned in California after they were shown to be highly vulnerable to hacking and malicious reprogramming, due to the lack of security features," Stein points out. "In an election surrounded by hacks, the use of systems that have been demonstrated to be easily hacked should concern every American."