Hillary Clinton slams Trump admin. over private emails: 'Height of hypocrisy' "They didn't mean any of it," Hillary Clinton told an interviewer on Monday.

 -- Hillary Clinton hit back at Donald Trump's White House after The New York Times reported on Monday that at least six administration officials communicated about government business through private emails.

"It's just the height of hypocrisy," she said in an interview with SiriusXM's Zerlina Maxwell after being asked to respond to the news on Monday.

Trump and his supporters repeatedly attacked Clinton before the 2016 presidential election for her use of a private email server during her time as secretary of state. "They didn't mean any of it," she said. "If they were sincere about it, I think you'd have Republican members of Congress calling for an investigation. I haven't heard that yet."

Clinton called her use of a private server "a dumb mistake but a dumber scandal" and said she regrets that the country "had to go through it."

During the campaign, Trump repeatedly called for an investigation of her use of the private server and said in a debate that Clinton would "be in jail" if he was in charge.

A White House official who spoke with ABC News did not dispute the Times' report that at least six administration officials occasionally used private email to communicate about official business since Trump took office.

The Times' report names the following current and former officials as those who communicated at times through a personal account: senior adviser Jared Kushner, former chief strategist Steve Bannon, chief economic adviser Gary Cohn, adviser Ivanka Trump, former chief of staff Reince Priebus and senior policy adviser Stephen Miller.

While it is not illegal for White House staffers to use personal email accounts, they must forward all work-related communications to their official White House email accounts.

White House press secretary Sarah Sanders confirmed this for ABC News today.

"All White House personnel have been instructed to use official email to conduct all government-related work," she said. "They are further instructed that if they receive work-related communication on personal accounts, they should be forwarded to official email accounts."

ABC News' Alexander Mallin and Katherine Faulders contributed to this report.