As construction begins on US President Donald Trump's new $250m (£187m) White House ballroom, mystery continues to swirl around the identities of the wealthy donors and corporations paying for it.

Groundbreaking for the ornate 90,000 sq ft (8,360 sq m) project began on Monday, with excavators and construction workers tearing out portions of the East Wing.

The US president has said that he personally will pay for significant portions of its construction, and suggested that some still anonymous donors would be willing to spend more than $20m to complete the project.

The funding model has sparked concern among some legal experts, who say it may amount to paying for access to the administration.

"I view this enormous ballroom as an ethics nightmare," Richard Painter, a former chief ethics lawyer in the Bush White House between 2005 and 2007, told the BBC.

"It's using access to the White House to raise money. I don't like it," he added. "These corporations all want something from the government."

A dinner for potential donors held at the White House on 15 October included senior executives from prominent US companies including Blackstone, OpenAI, Microsoft, Coinbase, Palantir, Lockheed Martin, Microsoft, Amazon and Google.

Also present was Woody Johnson, the owner of the New York Jets NFL team, and Shari and Edward Glazer,........

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