Nicole Kirby looks over results during a statewide presidential election recount Thursday, Dec. 1, 2016, in Milwaukee. The first candidate-driven statewide recount of a presidential election in 16 years began Thursday in Wisconsin. (Morry Gash/AP)

Supporters of President-elect Donald Trump are moving aggressively to challenge Green Party presidential candidate Jill Stein’s push for a recount in three states, filing legal challenges and criticizing the effort as quixotic and ill-conceived.

Trump and his backers have filed challenges the past two days in Michigan, Wisconsin and Pennsylvania, which were critical to Trump’s surprise victory last month because they punctured the so-called blue wall of states expected to carry Democrat Hillary Clinton to victory. Trump narrowly won the trio of states.

Michigan Attorney General Bill Schuette (R) on Friday tweeted that Stein’s request was “an expensive & a risky threat” as he announced he had filed an emergency motion with the Michigan Supreme Court to stop it.

Stein, who has raised millions of dollars from supporters to help pay for the costly recount efforts, blasted back at what she called “a politically motivated attempt by Bill Schuette to side with Donald Trump in opposition to a fair and accountable voting system.’’ She added in a statement that “citizens in Michigan and across the country of every political party have expressed their concerns around our voting system and deserve to have their votes counted.’’

[Shouting match erupts between Clinton and Trump aides]

Stein has raised concerns about possible hacking or other irregularities in the vote in the three states, but has presented no evidence of malfeasance. Election officials in all three states have expressed confidence in their results, and voting rights experts have said the effort is highly unlikely to overturn the results that are sending Trump to the White House.

Clinton’s campaign has joined Stein’s recount effort, though her team has said it does not expect the outcome of the election to change. The Clinton campaign had no immediate comment on Friday.

In Wisconsin, where Trump defeated Clinton by one percentage point, a recount is underway. But Great America PAC and Stop Hillary PAC, both pro-Trump groups, said Friday they had filed a legal challenge a day earlier in federal court in conjunction with a Wisconsin voter to stop the new count. Stein’s team said Friday that it will fight the challenge.

“Citizens in Wisconsin and across the country have made it clear that they want a recount and deserve to see this process through to ensure integrity in the vote,” Stein attorney Matthew D. Brinckerhoff said in a statement.

In Pennsylvania, where Stein has acknowledged the path to forcing a recount is more difficult but has initiated an effort to do so nonetheless, attorneys for Trump filed an objection to Stein’s request in state court on Thursday.

“Even with the heroic efforts by state and local elections officials involved in the recounts, as well as expeditious review by this Court, Stein’s proposed process will last weeks, perhaps even months. Either way, her request puts Pennsylvania at grave risk of having not certified its Presidential electors by December 13, the deadline for doing so,” says the filing.

On Friday, the focus of the escalating battle was in Michigan, as the Board of State Canvassers deadlocked 2-2 over an objection that attorneys for Trump filed Thursday against Stein’s recount request. Trump argued that Stein cannot, as the state’s fourth-place finisher, claim that she is “aggrieved” by the way the vote unfolded and that there isn’t enough time to complete the recount by the Dec. 13 deadline to certify Michigan’s election results.

Retired U.S. Marine Corps General James Mattis has been chosen to be secretary of defense by President-elect Donald Trump, according to people familiar with the decision. (Jenny Starrs/The Washington Post)

Because of the deadlock, the office of Michigan Secretary of State Ruth Johnson (R) said in a tweet that “the recount is expected to commence early next week, barring court action.”

Schuette then filed his emergency motion with the Michigan Supreme Court. It was not immediately clear whether a hearing has been set. The earliest a Michigan recount could start would be next week.

Meanwhile, the president-elect resumed his schedule of transition meetings at Manhattan’s Trump Tower on Friday, bringing in two well-known experts on foreign policy. The president-elect met with Robert M. Gates, who served as defense secretary under President Obama and had derided Trump as “unqualified and unfit to be commander-in-chief” in a September op-ed in the Wall Street Journal.

Gates spoke briefly with reporters afterward, saying he had praised Trump’s selection of retired Marine Gen. James N. Mattis as defense secretary, which Trump announced Thursday. “I told him I thought his selection of General Mattis to be secretary of defense was terrific, very supportive,” said Gates, who declined to answer further questions.

Trump also sat down with John Bolton, a former ambassador to the United Nations. He was at one point considered a candidate for secretary of state, but Kellyanne Conway, one of Trump’s top advisers, told Fox News on Friday that Trump has narrowed that search to four finalists. According to Conway, they are 2012 GOP presidential nominee Mitt Romney, former New York City mayor Rudy Giuliani, retired Army Gen. David Petraeus and Sen. Bob Corker (R-Tenn.), chairman of the Senate Foreign Relations Committee.

Opponents of Romney have waged an extraordinary public campaign against his nomination for the post and urged Trump to reward Giuliani for his loyalty during the campaign. It is unclear when Trump will make a final decision.

Alice Crites contributed to this report.