Green Party presidential candidate Jill Stein, center, takes questions from reporters in October. (D. Ross Cameron/AP)

President-elect Donald Trump and Green Party candidate Jill Stein continued raising competing doubts about the election on Monday, with Trump's transition team voicing concerns about voter fraud without providing evidence and Stein taking legal action to trigger a recount in Pennsylvania, one of three states she has targeted for additional scrutiny.

Trump on Monday was also officially declared the winner in Michigan by a slim margin. Stein announced plans to force a recount there on Wednesday. In Wisconsin, where Stein asked for a recount last week, elections officials on Monday announced a timeline and procedure for it.

In a conference call with reporters, Jason Miller, communications director for the Trump transition team, read a statement from the president-elect stating his disapproval of Stein's recount efforts.

“The people have spoken and the election is over,” Miller said. He later added: “It is important to point out that with the help of millions of voters across the country, the president-elect won 306 electoral votes on Election Day, the most of any Republican since 1988.”

Miller also echoed Trump's Sunday accusations of widespread voter fraud, which have not been backed up by any evidence.

“I do think that's an issue of concern, the fact that there's a concern that so many voted who were not legally supposed to,” Miller said. Asked for evidence, he cited studies about voter registrations conducted before the election but presented no specific proof of his claims that has emerged since the vote was conducted.

Stein, who finished well behind Trump and Democratic nominee Hillary Clinton, announced that she filed a legal petition in Pennsylvania on behalf of 100 voters “to protect their right to substantively contest the election in Pennsylvania beyond the recounts being filed by voters at the precinct level.”

“Americans deserve a voting system we can trust,” Stein said in a statement. “After a presidential election tarnished by the use of outdated and unreliable machines and accusations of irregularities and hacks, people of all political persuasions are asking if our election results are reliable. We must recount the votes so we can build trust in our election system.”

But Stein acknowledged in a Sunday video that it would be difficult to force a recount in Pennsylvania and would require her to “jump through some hoops.”

Republicans raised doubts Monday that Stein's argument would prevail.

“Our General Counsel has reviewed the Election Contest and said it is totally and completely without any merit. It does not even allege any facts to support its wild claim that the ‘discontinuity’ of pre-election polls reported by the media showing that Hillary Clinton would win and the actual results could only have occurred through computer hacking originated by a foreign government,” said Pennsylvania Republican Party Chairman Rob Gleason in a statement.

Stein said she has raised $ 6.5 million from more than 137,000 donors for the recount efforts. Because of the margins, the states are not absorbing the costs of recounting the votes.

In Michigan, the Board of State Canvassers certified Trump's win over Clinton by 10,704 votes out of about 4.8 million cast. Stein's team said it plans to demand a statewide hand-recount on Wednesday, in accordance with the 48-hour deadline to do so.

In Wisconsin, where Trump defeated Clinton by a percentage point, the bipartisan state Elections Commission announced plans to begin a recount on Thursday, provided that proper payment for the recount has been received by the state. It rejected the Stein campaign’s request for a statewide hand recount, instead leaving it to each county to decide whether to use a machine or not. The Stein campaign said it was filing a legal challenge to trigger an all-hand recount.

The Clinton campaign said during the weekend that it would join the recount effort even though the team does not expect the outcome to be reversed.

Paul Kane contributed to this report