The emails are said to be from the account of a White House staffer and Clinton campaign worker
A hacking group has posted what it alleges are emails from the account of a White House staffer who is also a Hillary Clinton campaign worker.
The DC Leaks group has also tweeted what it says is a photo of Michelle Obama's passport, although some questions have been raised about whether or not the image is genuine.
The DC Leaks website has hosted previous leaks, including emails from the account of former secretary of state Colin Powell.
Researchers have previously claimed the site is linked to suspected Russian cyberattacks which targeted US politicians and institutions.
According to DC Leaks, the latest emails are from the Gmail account of Ian Mellul, who is said to coordinate with US secret service and local law enforcement to ensure the safety of the US First Lady and Vice President during official trips.
The emails published are said to have been sent between February 2015 and July 2016.
The alleged image of Mrs Obama's passport has been the source of debate, with Engadget suggesting it looks "like a bad photoshop job".
However others have suggested some disputed details could be accurate, such as the five-year passport duration - which matches the amount of time special passports for US government officials are issued for.
Speaking to Politico, the US secret service said it was aware of "the alleged email hacking of a White House employee", but added that they "do not provide information regarding investigations".