Since declaring his support for Donald Trump in July of last year and subsequently spending more than $250m on his re-election effort, Elon Musk has rapidly accumulated political influence and positioned himself at the heart of the new administration.
Workers at the US Agency for International Development (USAid) were told to stay out of its Washington office after its website went dark over the weekend, with Secretary of State Marco Rubio announcing on Monday it would come under his control.
Joni Ernst is accusing USAID of intimidating and threatening her team in a brazen effort to obstruct congressional oversight.
The move is part of Trump's — and his billionaire ally Elon Musk's — radical drive to shrink the US government, which has shocked Washington and caused angry protests from Democrats and the human rights community.