WATCH: Blumenthal grills FBI Director Kash Patel on firing Iran specialists days before U.S. launched war

Sen. Richard Blumenthal, D-Conn., asked FBI Director Kash Patel why he fired a dozen agents and staff members from a counterintelligence unit "specifically tasked with monitoring threats with Iran," days before the U.S. launched an attack against the country.

Watch the clip in the video player above.

"I am astonished that this kind of action was taken," Blumenthal said.

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Patel said the agents, who worked in a group called CI-12, "failed to meet the standards of the FBI." At the time of the firings, in February, Patel said the agents were part of an investigation into President Donald Trump's mishandling of classified documents.

"I think what's most important is to not have a weaponized FBI, and I will endeavor every single day to make sure we have no one there that is doing that," Patel said.

Blumenthal pushed back, saying the firings "not only politicized but weaponized the FBI against its own employees."

"They were assigned to it. They had no choice,"  Blumenthal said. "What was the reason for firing them?"

"Those individuals were terminated for weaponizing the Federal Bureau of Investigation," Patel said.

Patel is testifying in an oversight hearing on the nation's lead law enforcement agency, which has recently touted a drop in crime nationwide.