President-elect Donald Trump vowed on Wednesday to step back from running his global business empire to avoid conflicts of interest, as concern over his dual role mounts ahead of the Republican’s inauguration on Jan. 20.

Mr. Trump, a real estate magnate who owns hotels and golf resorts from Panama to Scotland, said he will spell out at a Dec. 15 news conference how he will separate himself “in total” from his worldwide business holdings, which include a winery, modeling agency and a range of other businesses.

His company, the Trump Organization, previously said it was looking at new business structures with the goal of transferring control of his portfolio to Donald Trump Jr., Ivanka Trump and Eric Trump — three of his adult children who are involved with the company.

His children also are on the executive committee of his White House transition team.

Mr. Trump gave few details in a series of early morning tweets on Wednesday, but said “legal documents are being crafted which take me completely out of business operations” and noted his children will attend the news conference.

A brand name around the globe, Mr. Trump previously argued that he did not need to separate himself from the Trump Organization, which includes a hotel down the street from the White House, a Manhattan tower where he lives and is running his transition to office, and a New Jersey golf course where he interviewed cabinet candidates earlier this month.

Mr. Trump said on Wednesday he is not required by law to alter his relationship with his business, but added: “I feel it is visually important, as president, to in no way have a conflict of interest with my various businesses.”

As the Republican heads toward taking over the White House from President Obama, scrutiny of potential conflicts has grown.

Mr. Trump’s businesswoman daughter Ivanka joined her father’s telephone call with Argentine President Mauricio Macri earlier this month and attended a meeting with Japanese Prime Minister Shinzo Abe, raising questions of possible conflicts of interest.

Rules on conflict of interest for executive branch employees do not apply to the president, but Mr. Trump will be bound by bribery laws, disclosure requirements and a section of the U.S. Constitution that prohibits elected officials from taking gifts from foreign governments.

Also on Wednesday, Green Party presidential candidate Jill Stein requested a multimillion-dollar full hand recount of Michigan’s presidential vote, making it the third state narrowly won by Republican Donald Trump where she wants another look at the results.

Dr. Stein earlier asked for recounts of the votes in Pennsylvania and Wisconsin, although Mr. Trump’s victory is highly unlikely to be reversed in any of the states.

While the election results show that Democratic candidate Hillary Clinton won the popular vote by more 2 million votes, Mr. Trump has won more than the 270 Electoral College votes needed to become the nation’s 45th president.

However, he claimed on Twitter early Sunday that he “won the popular vote if you deduct the millions of people who voted illegally.” He went on to claim, with no evidence presented, that there was “serious voter fraud in Virginia, New Hampshire and California.”

Virginia Gov. Terry McAuliffe, a Democrat who supported Mrs. Clinton, responded: “When you make an allegation, put proof behind it.”

Mr. Trump’s Twitter remarks added fuel to the growing push for the recount, igniting millions of dispirited Clinton voters and concerns about “cyber hacking,” possibly by foreign governments. Ms. Stein had netted $6.3 million by Monday to pay for the recounts, according to her campaign website.

Meanwhile Mr. Trump, a former reality TV star, has spent much of the last few weeks setting up his new cabinet and interviewing candidates for top jobs in his administration.

On Wednesday, Mr. Trump said he will nominate his chief campaign fundraiser Steven Mnuchin to become treasury secretary. Mr. Mnuchin said the administration would make tax reform and trade pact overhauls top priorities as the treasury seeks a sustained pace of 3 percent to 4 percent economic growth.

Mr. Mnuchin, a former Goldman Sachs banker, also signaled a desire to remove mortgage-finance companies Fannie Mae and Freddie Mac from government ownership, a move that could have wide-ranging ramifications for how Americans pay for their homes, and said banking regulations should be eased to spur lending.

Mr. Trump named Wilbur Ross, a billionaire known for his investments in distressed industries, as his nominee for commerce secretary. Both nominees will require confirmation by the U.S. Senate.

President-elect Trump also on Wednesday asked Preet Bharara, the top federal prosecutor in Manhattan appointed by President Obama in 2009, to stay in his role.

Mr. Bharara is known for pursuing a series of high-profile cases targeting public corruption and crime on Wall Street, and has won praise in New York for pursuing corruption investigations involving state and city politics, as well as financial crime.

Mr. Trump is considering Goldman Sachs President and Chief Operating Officer Gary Cohn, a former commodities trader, to head his White House budget office or to fill another position, a Trump transition official said.

Regulatory watchdog groups panned the Wall Street picks. Mr. Trump’s spokesman defended giving top economic jobs to Wall Street figures despite an election campaign pledge to “drain the swamp” of establishment figures in government.

“There’s nobody else who understands the challenges that American workers and businesses face,” Mr. Trump’s spokesman Jason Miller said.

Mr. Trump’s team also announced that Seema Verma has been chosen to be administrator of the Centers for Medicare and Medicaid Services.

Mr. Trump also was working to fill out his foreign policy team, but no decision appeared imminent on who the next secretary of state will be.

He met on Tuesday with former New York City Mayor Rudy Giuliani about the top diplomatic post, a transition aide said, and later dined with 2012 Republican nominee Mitt Romney, at a French restaurant near Central Park on Tuesday night.

Mr. Romney, who had slammed Mr. Trump during the campaign, made an impassioned statement in support of the president-elect after their meal.

Mr. Miller said Mr. Trump told him that “he thought the dinner went really well” and that there was good chemistry between the men, who are still getting to know each other.

Mr. Trump was to meet on Wednesday with another potential secretary of state pick, retired Marine Corps Gen. John Kelly.

So far, President-elect Trump’s cabinet appointees, which all require Senate confirmation, include:

• Steven Mnuchin, former Goldman Sachs executive and the campaign finance chairman for Mr. Trump’s campaign, as treasury secretary. Mr. Mnuchin has no political experience.

• Elaine L. Chao, former labor secretary under President George W. Bush and wife of Senate Majority Leader Mitch McConnell, as transportation secretary.

• Tom Price, orthopedic surgeon and six-term Republican congressman from Georgia who voted to repeal large provisions of the Affordable Care Act, as secretary of health and human services.

• Wilbur Ross, former banker and investor said to be worth $2.9 billion according to Forbes, as commerce secretary.

• Betsy DeVos, former chairwoman of the Michigan Republican Party, as education secretary.

• Nikki R. Haley, governor of South Carolina, as U.N. ambassador.

• Dr. Ben Carson, neurosurgeon and 2016 Republican presidential candidate, as secretary of housing and urban development.

• Mike Pompeo, a congressman from Kansas, current House Intelligence Committee member and former Army officer, as CIA director.

• Jeff Sessions, a U.S. senator from Alabama as U.S. attorney general. Sen. Sessions’ nomination for a federal judgeship was rejected in 1986 because of his comments and views that were highly sympathetic to white nationalists and racists.