Officials in Wisconsin are preparing to conduct a full recount of the votes from the US election in the state, which was narrowly won by Donald Trump.
A formal request for the recount was filed by the Green Party's Jill Stein.
Stein, the Green Party's candidate, has also pledged to file for recounts in Michigan and Pennsylvania.
The result would need to be overturned in all three states to change the outcome of the election.
Wisconsin, Pennsylvania and Michigan were battleground states where Trump edged out Hillary Clinton by relatively thin margins.
In a statement, the Wisconsin Elections Commission said that it had received two recount petitions from the Stein campaign and from Rocky Roque De La Fuente, a businessman who ran unsuccessfully to be the 2016 Democratic presidential nominee.
"The Commission is preparing to move forward with a statewide recount of votes for President of the United States, as requested by these candidates," said Wisconsin election commission administrator Michael Haas.
He said that the recount would begin in the week after Stein's campaign has paid the fee, which the commission was still calculating.
Stein's campaign needs to raise millions of dollars to cover the fees for the vote recount in all three states.
Stein's website said that nearly $5.3 million has already been raised toward a $7 million target. It said that this is enough to fund the recounts in Wisconsin and Pennsylvania.
Stein reportedly wants to make sure computer hackers did not skew the poll in favor of Trump.
Citing the hack of the Democratic National Committee of the Democratic Party in the run-up to the election and reports of breaches of voter registration databases in at least two states, Stein wrote in her petition for recount that Wisconsin uses both the optical scan and direct-recording electronic types of electronic voting machines, which are both susceptible to compromise.
"For the last decade, computer scientists have warned about the vulnerabilities of these machines, including that they can be breached without detection and even after certain security measures are put in place," Stein wrote.
She added that in Wisconsin there is evidence of voting irregularity, suggesting potential tampering of the voting machines in the 2016 presidential elections, as well as an increase in the number of absentee voters, which could be attributed to a breach of the state's voter database.
"The only way to know whether a cyber attack changed the result is to closely examine the available physical evidence -- paper ballots and voting equipment in critical states," wrote J. Alex Halderman, a computer science professor at the University of Michigan, in a post on Medium.com.
"Whether voting machines are connected to the Internet is irrelevant," Halderman wrote in a submission in support of Stein. As demonstrated by him in the laboratory in just a few seconds, anyone can install vote-stealing malware on a voting machine that silently alters the electronic record of every vote, he added.
Clinton team to take part in vote recount
Marc Elias, the Clinton campaign counsel, said that the campaign had not planned to seek a recount since its own investigation had failed to turn up any sign of hacking of voting systems.
"But now that a recount has been initiated in Wisconsin, we intend to participate in order to ensure the process proceeds in a manner that is fair to all sides," Elias said in a post on the website Medium.
Clinton's campaign should be legally represented in Wisconsin to be able to monitor the recount, he said.
If Stein follows through on promises for recounts in Pennsylvania and Michigan, "we will take the same approach in those states as well," Elias said.
On Saturday, president-elect Trump broke his silence on the multi-state vote-recount effort, calling the effort "ridiculous" and a scam.
"The people have spoken and the election is over," Trump. "We must accept this result and then look to the future...This recount is just a way for Jill Stein to fill her coffers with money, most of which she will never even spend on this ridiculous recount."
Trump and his transition team had been quiet on the recount effort until the Clinton team announced its participation, instead focusing on the latest additions to Trump's administration.
"As Hillary Clinton herself said on election night, in addition to her conceding by congratulating me, 'We must accept this result and then look to the future,' " Trump also said. "This is a scam by the Green Party for an election that has already been conceded."