A group of Republican senators Tuesday asked FBI Director Christopher Wray to investigate one of President Biden's Pentagon nominees over whether he allegedly disclosed classified information on social media after leaving the Obama administration. 

The group was led by Sens. Bill Hagerty, R-Tenn., and Tom Cotton, R-Ark. Hagerty himself last month alleged that Colin Kahl, the nominee for undersecretary of defense for policy, "may have been knowingly leaking, or otherwise disclosing on Twitter, sensitive information, including classified information." 

Kahl, who served as Biden's national security adviser when he was the vice president, disputed that he disclosed classified information in a response to the committee. He said that the Washington Post specifically was the source for at least one batch of tweets the senators have raised concerns about. 

But Hagerty called that letter "evasive," said the Washington Post story referenced didn't include all of the information that Kahl tweeted and said there were even more posts beyond those that contained classified information. 

PENTAGON POLICE OFFICER ARRESTED ON MURDER CHARGES AFTER OFF-DUTY FATAL SHOOTING

"Indeed, Kahl's March 23 written response raises more questions than it answers and may even further implicate him in the mishandling of classified information ad controlled unclassified information," Hagerty and the other GOP senators wrote. 

"We also have subsequently discovered additional Twitter posts by Kahl that deserve greater scrutiny," they continued. "In a series of Twitter posts on December 20, 2017, the nominee not only appeared to publicly confirm leaked classified information and controlled unclassified information contained in a news report... but also publicly claimed to have personally confirmed the accuracy of this leaked classified information and controlled unclassified information with 'multiple U.S. government officials."

The GOP senators said there should be "a comprehensive investigation" into Kahl "before Kahl's nomination is advanced in the Senate."

Kahl strongly denied sharing classified information last month.

"I have never publicly shared information I knew to be classified and take my obligations to protect classified information seriously," he wrote in his letter to the committee. "I was not present for the interagency meetings mentioned in the letter or in the referenced tweets. I had no direct access to any information in those meetings that may or may not have been classified."

Former U.S. Deputy Assistant Defense Secretary for the Middle East Colin Kahl participates in a panel discussion about Iran's nuclear program sponsored by The National Iranian American Council in the Rayburn House Office Building on Capitol Hill Feb. 21, 2012, in Washington, D.C. Kahl is a nominee for a top Pentagon role but faces sharp opposition from Republicans. (Chip Somodevilla/Getty Images)

Former U.S. Deputy Assistant Defense Secretary for the Middle East Colin Kahl participates in a panel discussion about Iran's nuclear program sponsored by The National Iranian American Council in the Rayburn House Office Building on Capitol Hill Feb. 21, 2012, in Washington, D.C. Kahl is a nominee for a top Pentagon role but faces sharp opposition from Republicans. (Chip Somodevilla/Getty Images) (Getty Images)

Kahl continued to say information on his tweets about Yemen and former President Trump's habits on consuming the Presidential Daily Brief were already public knowledge. 

"For example, in a media interview, then President-Elect Trump said in mid-December 2016 that he did not need daily intelligence briefings," Kahl wrote. "When asked shortly before his inauguration by a reporter about his preferences regarding intelligence information and briefings, President-Elect Trump expressed his desire for bullets or little information as was necessary... The other tweets referenced also do not contain any information I knew to be classified."

REPUBLICANS CHARGE BIDEN BUDGET LEAVES US MILITARY 'NEGLECTED'

The White House did not comment on the additional tweets about North Korea raised in Hagerty's new letter. 

Kahl has faced one of the most difficult paths to confirmation of any Biden official, and the Senate Armed Services Committee voted on party lines to advance his nomination. Beyond the tweets Republicans say might have violated national security, Kahl was a prolific Twitter user who was sharply critical of Republicans. 

Even moderate Republican Sen. Susan Collins of Maine said she opposes Kahl, citing his social media posts and past policy positions. 

"He warned of calamity following the relocation of the U.S. Embassy in Israel to Jerusalem, when instead we saw historically close Arab-Israeli ties in 2020," she said last month, according to Politico. "Some of Dr. Kahl’s actions have raised questions about his ability to work with Congress in a thoughtful and productive manner... If America is going to successfully confront our toughest national security challenges, we need a nominee for this position who will help bring Republicans and Democrats together."

Sen. Joe Manchin, D-W.Va., also a moderate, was the swing vote on the Armed Services Committee that allowed Kahl to advance to the Senate floor. With Manchin's support Kahl is likely to be confirmed when the final vote on his nomination happens. 

Sen. Bill Hagerty, R-Tenn., attends the Senate Foreign Relations Committee confirmation hearing for Wendy Sherman, nominee for deputy secretary of state, and Brian McKeon, nominee for deputy secretary of state for management and resources, in the Dirksen Building on Wednesday, March 3, 2021. Hagerty has led GOP opposition to Biden nominee for undersecretary of defense for policy nominee Colin Kahl. (Tom Williams/CQ-Roll Call, Inc via Getty Images)

Sen. Bill Hagerty, R-Tenn., attends the Senate Foreign Relations Committee confirmation hearing for Wendy Sherman, nominee for deputy secretary of state, and Brian McKeon, nominee for deputy secretary of state for management and resources, in the Dirksen Building on Wednesday, March 3, 2021. Hagerty has led GOP opposition to Biden nominee for undersecretary of defense for policy nominee Colin Kahl. (Tom Williams/CQ-Roll Call, Inc via Getty Images)

CLICK HERE FOR THE FOX NEWS APP

Last month dozens of former U.S. generals and flag officers backed Kahl in a letter to the Armed Services Committee, largely citing Kahl's work with Israel. 

"It is precisely because we support the U.S.-Israel alliance that we also support Colin Kahl to be the next Under Secretary of Defense for Policy," the top officers wrote. "Mr. Kahl’s thorough understanding of policy, military technology, and adversary capabilities has helped saved countless Israeli lives. Mr. Kahl’s early recognition of the potential value of Israel’s Iron Dome project, coupled with his tireless support for its funding, helped provide Israel with a crucial tactical and strategic advantage."

It's not clear when a final vote on Kahl's nomination will happen, or if the FBI will open an investigation into the nominee as the GOP senators requested. Senate Majority Leader Chuck Schumer, D-N.Y., has not yet filed cloture on Kahl's nomination, a procedural step necessary to get to a final vote. 

Fox News' Lucas Tomlinson, Kelly Phares and the Associated Press contributed to this report.