Once a key member of President Donald Trump's inner circle, a major campaign donor and a scene-stealing presence at Cabinet meetings, Elon Musk's relationship with the president has deteriorated into a bitter public feud since leaving the White House last week.

Donald Trump's aides scheduled a call between the U.S. president and Elon Musk for Friday after a huge public spat that saw threats fly over government contracts and included the world's richest man suggesting Trump should be impeached.