Attorney General Loretta Lynch is declining to comply with a probe into the Obama administration's secret efforts to send Iran $1.7 billion in cash earlier this year to avoid incriminating herself, according to The Washington Free Beacon.

Florida Sen. Marco Rubio and Kansas Rep. Mike Pompeo wrote in a letter that Lynch chose to "essentially plead the Fifth," after the Republican lawmakers presented her with questions about the cash payment.

In an Oct. 24 response, Assistant Attorney General Peter Kadzik responded for Lynch, refusing to answer the questions and telling the lawmakers that they are barred from publicly revealing details about the payment.

"Disclosure of this information beyond members of the House and Senate and staff who are able to view them could adversely affect the diplomatic relations of the United States, including with key allies," Kadzik wrote.

"It is frankly unacceptable that your department refuses to answer straightforward questions from the people's elected representatives in Congress about an important national security issue," Rubio and Pompeo wrote.

"Your staff failed to address any of our questions, and instead provided a copy of public testimony and a lecture about the sensitivity of information associated with this issue. As the United States' chief law enforcement officer, it is outrageous that you would essentially plead the Fifth and refuse to respond to inquiries."

They attached the questions again and requested that Lynch send answers by Nov. 4.

Rep. Pompeo rebuked the Obama administration about the issue. "Who knew that simple questions regarding Attorney General Lynch's approval of billions of dollars in payments to Iran could be so controversial that she would refuse to answer them?" he asked.

"This has become the Obama administration's coping mechanism for anything related to the Islamic Republic of Iran — hide information, obfuscate details, and deny answers to Congress and the American people."

Pompeo hopes the administration would begin to take their "professional, and moral," obligations seriously.

Details about the Iran deal are being kept in a secure facility, and any lawmakers who have clearance to view them must give up cell phones and are not allowed to take notes, the Free Beacon first disclosed.

Other efforts have been launched to unearth a full accounting of the Iran negotiations.

One senior congressional source told the Free Beacon that the administration "appears to be "running for cover" from the issue.

"Evidently Attorney General Lynch and the Department of Justice have decided 'refusal to cooperate' is their best strategy. But this is dangerous and ultimately won't protect them from anything," the source said.

The Iran deal is an "unfolding disaster," Rubio wrote in an op-ed for CNN.