The new Secret Service director is giving as good as he gets … firing back at least one U.S. Senator grilling him over his agencies failures in protecting Donald Trump the day of the assassination attempt.

Acting Dir. Ronald Rowe went toe-to-toe with Sen. Josh Hawley Tuesday, and things got extremely heated when Hawley demanded to know who Rowe had fired over the security failures in Butler, PA.

At first, Rowe calmly explained that he was waiting for the results of the FBI investigation to determine next steps — but when Hawley barked back that there were obvious failures because the “former president was shot” … Rowe snapped.

He fired back with a reference to the JFK assassination in Dallas, barking … “Sir, this could have been our Texas School Book Depository. I have lost sleep over that for the last 17 days, just like you!!!”

Hawley interjected, “Then fire somebody!” … which only got Rowe more heated.

Watch the exchange play out — the hearing continued after this, but the tone was much different, as Rowe was clearly done being a punching bag.