Story highlights "When you see these thugs being thrown into the back of a paddy wagon. You just see them thrown in -- rough. I said, 'Please don't be too nice,'" Trump said Friday

DEA Acting Administrator Chuck Rosenberg in email to employees: "I write to offer a strong reaffirmation of the operating principles to which we, as law enforcement professionals, adhere."

Police departments have criticized Trump's comments

Washington (CNN) Less than 24 hours after President Donald Trump told an audience full of police officers in New York to be "rough" on suspects, the acting head of the Drug Enforcement Administration sent his employees an email that rebuked the President's suggestion.

"The President, in remarks delivered yesterday in New York, condoned police misconduct regarding the treatment of individuals placed under arrest by law enforcement," DEA Acting Administrator Chuck Rosenberg wrote in a message to DEA's "Global Distribution" list Saturday.

JUST WATCHED Trump to police: Don't be too nice to suspects Replay More Videos ... MUST WATCH Trump to police: Don't be too nice to suspects 06:08

"In writing to you, I seek to advance no political, partisan, or personal agenda. Nor do I believe that a Special Agent or Task Force Officer of the DEA would mistreat a defendant. I know that you would not," Rosenberg added. "So, why do I write? I write to offer a strong reaffirmation of the operating principles to which we, as law enforcement professionals, adhere. I write because we have an obligation to speak out when something is wrong. That's what law enforcement officers do. That's what you do. We fix stuff. At least, we try."

Trump, in a speech meant to focus on effort to combat the brutal gang MS-13 Friday, told police officers to be "rough" with suspects.

"When you see these thugs being thrown into the back of a paddy wagon. You just see them thrown in -- rough. I said, 'Please don't be too nice,'" Trump said to applause, referring to officers shielding prisoners' heads with their hands. "Like, don't hit their head and they've just killed somebody, don't hit their head. I said, 'You can take the hand away, OK?'"

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