Hopes for a quick vote on Sen. Markwayne Mullin’s nomination as Homeland Security secretary hang on questions about secretive travel the Oklahoma Republican undertook as a House member a decade ago that are now being examined by his Senate colleagues.

Mullin was questioned extensively about the matter Wednesday by Sens. Rand Paul (R-Ky.) and Gary Peters (D-Mich.), the chair and ranking member, respectively, of the Senate Homeland Security and Governmental Affairs Committee.

Testifying under oath Wednesday, Mullin said he participated in what he described as “official travel” and a “classified trip” as part of a “special program inside the House” that went from 2015 to 2016. He said he was not a member of the House Intelligence Committee at the time and refused to answer further questions outside of a classified setting.

The attention on the matter came after Peters raised questions about Mullin’s past claims suggesting he had traveled to war zones and had first-hand exposure to combat environments despite his lack of a military background.

After the hearing adjourned Wednesday afternoon, Mullin joined Paul, Peters and other members of the committee in the Senate’s classified briefing facility.

“I’m one of these people who think that we silo off too much information from the public,” Paul told reporters after the hearing. “When we’re going to war, they tell eight people, it’s like, ‘Oh, we’ve notified Congress.’ So I don’t think that is adequate.”

“It makes people curious when you say, I’m doing secret missions for somebody, but I won’t tell you who, and only four people in the world know about those,” Paul added.

Mullin said only four people were “read into” the program in question and declined to say publicly what agencies or committees were involved.

“It’s a little difficult for us to go ask about a program that has no name and we have nobody that we know to talk to about it,” Peters said before Mullin agreed to the classified meeting. “So I don’t know how we would begin doing this without your cooperation.”

The questions about the shadowy travel erupted after Mullin’s nomination suddenly turned rocky after Paul questioned his temperament and fitness for office based on his past comments and behavior.

Paul later confirmed he would oppose Mullin’s nomination but said he still intended to hold a committee vote Thursday. To get through the panel with Paul opposed, Mullin will need the support of at least one Democrat.

Sen. John Fetterman (D-Pa.) has suggested he is inclined to support Mullin but declined to confirm Wednesday he would vote for him. Fetterman was among the senators spotted entering the classified meeting following the hearing.

“I’m willing to hold the vote tomorrow, but you brought this up that you were on a super secret mission,” Paul told Mullin at the hearing.

“No, I did not say super secret,” Mullin responded. “I said it was classified.”

Senate Majority Leader John Thune said he is confident Sen. Markwayne Mullin will be confirmed as the next secretary of Homeland Security despite a contentious exchange with fellow GOP Sen. Rand Paul at a hearing Wednesday.

Paul, the chair of the Homeland Security and Governmental Affairs Committee, sharply questioned the Oklahoma senator about past remarks that he “understood” why Paul suffered a heinous assault from a neighbor in 2017. Mullin refused to apologize for the remark.

“Those two obviously have some history, and it’s, you know, personal stuff,” Thune said. “They’ve got to work through it. I mean, in the end, this is about the job, and it’s about making sure that we got the right person there. I think Markwayne is the right person for the job.”

Asked if he was still confident Mullin can be confirmed, Thune said, “Yeah.”

Paul has scheduled a committee vote on Mullin for Thursday. While Paul’s vote is in serious doubt, Mullin could win over Democratic Sen. John Fetterman of Pennsylvania, who has expressed support for Mullin previously and said Wednesday he would approach the nomination “with an open mind.”

“I haven’t been rocked by some mic-dropping kind of moments,” Fetterman told reporters after the hearing.

Sen. Markwayne Mullin said he regretted calling Alex Pretti “deranged” but stopped short of offering a direct apology to Pretti’s family.

“I shouldn’t have said that,” the Oklahoma Republican said during his confirmation hearing Wednesday to serve as the next Homeland Security secretary. He was referring to his past comments regarding the U.S. citizen killed by federal immigration enforcement agents in Minnesota back in January, who some conservatives in the immediate aftermath labeled a “domestic terrorist.”

It was a stronger concession than Mullin gave just moments earlier, when he refused to apologize for calling Sen. Rand Paul (R-Ky.), the chair of the Homeland Security and Government Affairs Committee, a “snake.” Still, when pressed by the committee’s top Democrat, Sen. Gary Peters of Michigan, Mullin would not commit to apologizing to Pretti’s family until the conclusion of an investigation into the incident.

“If I’m proven wrong, then I will,” Mullin said.

Regarding Renee Good, another U.S. citizen killed by immigration enforcement officers in Minnesota earlier this year, Mullin refused to retract comments he made at the time of Good’s death, specifically that agents were justified in killing her. He told BLN in January that agents “had the right to defend themselves.”

He said he would wait for the findings of the investigation into Good’s killing to comment further; Sen. Richard Blumenthal (D-Conn.) countered that the Trump administration is currently blocking state and local inquiries.