Steven Mnuchin, national finance chairman of President-elect Donald Trump's campaign, talks with reporters at Trump Tower on Tuesday in New York. (Carolyn Kaster/AP)

President-elect Donald Trump appears close to filling two key Cabinet positions with veteran investors who have close ties to Wall Street, according to one of his major donors and longtime business partners.

Billionaire investor Carl Icahn tweeted Tuesday that he had spoken to Trump and that the president-elect was considering naming his campaign finance chairman, Steven Mnuchin, and economic adviser Wilbur Ross to lead the Treasury and Commerce departments. It remained unclear who would receive which title, but Mnuchin has been considered by Trump insiders as a top pick for Treasury and Ross as an option for both jobs.

“Both would be great choices,” Icahn tweeted. “Both are good friends of mine but more importantly, they are two of the smartest people I know.”

Mnuchin joined Trump’s campaign in the spring and worked closely with his economic advisers to put together Trump’s proposal to dramatically cut taxes for individuals and businesses. Mnuchin was at the Trump’s team headquarters at Trump Tower in New York on Tuesday morning but declined to comment on whether he has been offered a job in the administration.

“We're working on the economic plan with the transition, making sure we get the biggest tax bill passed, the biggest tax changes since Reagan,” he said.

Ross is a venture capitalist who has focused on buying business in distress, including a landmark deal to buy bankrupt steelmaker LTV in the early 2000s as well as a host of manufacturing companies. He was named to Trump’s economic team over the summer.

Ross helped map out Trump’s plan for his first 100 days in office. In an interview with Yahoo Finance last week, he played down concerns that Trump’s incendiary campaign rhetoric and pledge to label China as a currency manipulator could launch the country into a trade war.

“Everybody says, 'Oh he’s going to slap a 45 percent tariff on everything out of China.' That’s not what he said, and it’s not what he intends,” Ross said.

Both Ross and Mnuchin are well-known on Wall Street. Mnuchin followed in his father’s footsteps by joining Goldman Sachs, eventually rising to become chief information officer in 1999. He later founded a private-equity firm, Dune Capital, and led the purchase of now-defunct subprime-mortgage lender IndyMac during the financial crisis. Mnuchin also helped finance blockbuster Hollywood movies such as “Avatar” and “Suicide Squad.”

“I really came to admire him for his knowledge of the tax system and his free-market principles,” said Stephen Moore, who also served on Trump’s economic advisory team and is a distinguished fellow at the Heritage Foundation.

Moore said a final decision on key economic positions was “imminent.” But the picks could come under fire from Democratic lawmakers on Capitol Hill. At a conference hosted by the Wall Street Journal on Tuesday, Massachusetts Sen. Elizabeth Warren criticized Trump's use of lobbyists and industry insiders on his transition team.

"I think that the clearest point that comes out of this election is that the American people do not want Wall Street to run their government," Warren said. "They do not want corporate executives to be the ones who are calling the shots in Washington."

During his campaign, President-elect Donald Trump repeatedly vowed to "drain the swamp" in D.C. and rid the federal government of political elites and lobbyists. But just days into his transition to president, Trump seems to be doing the opposite. (Deirdra O'Regan/The Washington Post)