Musk warned federal employees over the weekend that non-responses to the email would "be taken as a resignation."

Billionaire Elon Musk has said there is widespread fraud taking place in the payment of "federal entitlements" like Social Security. Social Security benefits are paid to more than 70 million Americans on a monthly basis, and help form the bedrock of income for many retirees, survivors of deceased claimants and disabled people.

The Trump administration claimed the Social Security Administration gives payments to dead people. SSA audits revealed it happens less than suspected.