GOP lawmakers are calling for transparency about the protection of whistleblowers in the ongoing investigation into the two assassination attempts against former President Trump.

In a letter penned to Department of Homeland Security (DHS) Secretary Alejandro Mayorkas, senators Chuck Grassley, R-Iowa, and Ron Johnson, R-Wis., expressed concern after whistleblowers revealed that Secret Service employees were required to sign nondisclosure agreements (NDAs).

The whistleblowers alleged they were required to sign NDAs to access briefings on "sensitive reporting" relevant to their work to protect former President Trump.

Photos, shared in the letter to Mayorkas, showed screenshots sent to Secret Service agents requesting them to sign a NDA.

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The senators are now requesting that DHS reveal the scope of the NDAs and if employees were required to sign statutorily-required anti-gag language.

In their letter, the senators referred to the Whistleblower Protection Enhancement Act (WPEA).

The WPEA states that "no federal agency nondisclosure policy, form, agreement, or related documents may be implemented or enforced if it does not contain specific language notifying the employee of their rights to disclose waste, fraud, abuse, or misconduct to Congress, an Inspector General, or the Office of Special Counsel (OSC)."

Senators Grassley and Johnson also requested that the DHS provide the threat assessment used to justify sending the NDAs.

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They also requested that the agency share how the requirement altered and affected Trump's and any other government officials' protective details.

The senators highlighted the need for DHS to provide transparency about whistleblowers' rights.

"The importance of whistleblowers knowing their rights under the law cannot be stated enough, and federal agencies should encourage their employees to disclose allegations of waste, fraud, and abuse through all appropriate channels," they said. "Federal agencies cannot conceal their wrongdoing behind illegal non-disclosure policies and related actions."

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Fox News Digital has reached out to the DHS for comment.