A second email asking government workers to detail what they did in the last week went out to some agencies on Saturday.
Unions for federal employees are suing to stop Musk's "What did you do last week" threat.
Individual federal agencies will handle what actions to take against employees who did not respond to an email asking them to ...
The Department of Defense is among several U.S. federal agencies pushing back against the email, which was sent out Saturday.
Elon Musk posted Saturday on his social media site that failure to reply to the email would be taken as a resignation.