President-elect Donald Trump arrives at the Trump National Golf Club Bedminster clubhouse in Bedminster, N.J. (Carolyn Kaster/AP)

In the days since Donald Trump became president-elect, there has been ever-growing concern that his sprawling global business empire could present conflicts of interest once he takes office — so much so that congressional phone lines have been jammed this week with calls for an investigation.

Trump brushed off that concern in a tweet Monday evening, writing: “Prior to the election it was well known that I have interests in properties all over the world. Only the crooked media makes this a big deal!”

For months, media outlets have reported on the unprecedented complications that would come with electing a businessman who had active deals in a number of countries, including many where the United States maintains sensitive diplomatic ties. At least 111 Trump companies have done business in 18 countries and territories across South America, Asia and the Middle East, a Washington Post analysis of Trump financial filings shows. Some of these deals were launched while Trump was campaigning, including a potential hotel project in oil-rich Saudi Arabia.

On the campaign trail, Trump said that he would hand over control of the Trump Organization to his children, although he and his aides never detailed what steps would be taken to fully separate Trump from the business dealings. Now that he is the president-elect, Trump has put his three oldest children on his presidential transition team and has seemed to ignore calls that he sell his company or give his business interests over to an independent manager or “blind trust.”

If he doesn't do so, Trump's international properties could become targets for attack or a back-channel for foreign dealmakers trying to please the Trump Administration. Trump also runs the risk of violating the Emoluments Clause of the Constitution, which states that elected leaders cannot “accept of any present, emolument, office or title, of any kind whatever, from any king, prince or foreign state” without permission from Congress.

Donald Trump has a lot of potential conflicts of interest as president – but there's no law that specifically requires a commander in chief to remove themselves from all of their business interests. The Fix's Peter W. Stevenson explains why presidents usually put their assets in a "blind trust" to avoid problems. (Peter Stevenson/The Washington Post)

Eight minutes after sending the tweet about his foreign business, Trump sent another that waded into British politics and urged Prime Minister Theresa May to appoint Nigel Farage, the U.K. Independence Party leader and one of the architects of the successful Brexit campaign, as Great Britain's ambassador to the United States. May's spokesman said there is no vacancy.

“Many people would like to see @Nigel_Farage represent Great Britain as their Ambassador to the United States. He would do a great job!” Trump tweeted.

It was a striking move for the U.S. president-elect to interfere in the domestic politics of another country. Trump's advocacy is sure to cause waves in Britain, considering the complicated relationship between May and Farage. Trump has grown close to Farage over the past year and saw his own victory as an extension of the global populist movement that propelled the Brexit campaign across the Atlantic. Farage campaigned with Trump earlier this year in Mississippi, appeared at the second presidential debate as a Trump surrogate and, a few days after the election, paid Trump a visit in New York.

“We already have an excellent ambassador to the U.S.," May's spokesman said in response to Trump's tweet.

Drew Harwell and Anu Narayanswamy contributed to this report.