The chairman of the Senate Foreign Relations Committee told Breitbart News Thursday Sen. Marco Rubio (R.-Fla.) is the only Republican member of his committee he suspects could vote against the confirmation of former Exxon Mobil CEO Rex Tillerson for secretary of state.

“I am not aware of anyone else who has the concerns of Rubio,” said Sen. Robert P. Corker Jr. (R.-Tenn.), who became the chairman in 2015 after the Republicans won the Senate majority in the 2014 midterms.”You’re going to have to speak to Senator Rubio about that.”

Corker said it was his understanding that Rubio was going to line up time to meet with Tillerson before the committee votes.

Republicans hold a 52-to-48 advantage in the Senate, so three Republican defections spell defeat for any of President-elect Donald J. Trump’s nominees.

Corker said he is confident that Tillerson has the votes for confirmation because a number of Democrats, whom he would not name, have reached out to him about Tillerson and they have signaled a willingness to support his confirmation.

Rubio told reporters after a closed door meeting of the Foreign Relations Committee that he has not made a decision.

“I’ve got some things I got to work through,” the Florida senator said.

“We have to work through the process, when we are ready to announce, you’ll be be the first to know,” he said as he watched elevator doors close, momentarily blocking his escape.

Rubio met with Tillerson Monday, but the senator would not say whether there would be another meeting.

The chairman said the reason Tillerson’s second day of testimony was cancelled was to create space for office visits–and his belief that each senator got enough time asking questions.

“Every committee member got at least 24 minutes yesterday,” he said. Another committee chairman told Corker his senators got one round of five minutes each and that was it.

In his questioning of Tillerson, Rubio was combative, especially on the subject of Russian president Vladimir Putin.

In a typical exchange, Rubio, the lawyer, asked Tillerson, the engineer, if he agreed that Putin was killing political opponents in Russia and overseas.

Tillerson: I do not have sufficient information to make that claim. Rubio: Are you aware that people who oppose Vladimir Putin wind up dead all over the world? Poisoned and shot in the back of the head? Do you think that was coincidental? Or do you think it is quite possible or likely–as I believe–that they were part of an effort to murder his political opponents? Tillerson: Well, people, who speak up for freedom in regimes that are oppressive are often at threat and these things happen to them. In terms of assigning specific responsibilities, I would have to have more information. As I have indicated, I feel its important that in advising the president, if confirmed, that I deal with facts that I deal with sufficient information, which means having access to all information and I am sure there is a large body of information that I have never seen because it is in the classified realm. I look forward upon being confirmed becoming fully informed. But, I am not willing to make conclusions on what is publicly available or publicly reported. Rubio: None of this is classified, Mr.Tillerson. These people are dead. Political opponents– Tillerson: Your question was people, who were directly responsible for that. I am not disputing that these people are dead.

Corker said he was concerned that in Wednesday’s testimony, there was the impression left that Tillerson lied about whether or not he or Exxon Mobil lobbied against economic sanctions levied on Russia in response to Russian annexation of Crimea and other parts of eastern Ukraine.

Tillerson testified that he and his company did not lobby against the sanctions, but the ranking member of the committee, Sen. Robert Menendez (D.-N.J.), confronted Tillerson with documents Exxon Mobil filed to report its lobbying efforts on Capitol Hill.

The New Jersey senator said he was confused as to how Tillerson could testify that he did not lobby the sanctions bill, sponsored by Mendendez, if his company reported that it was in fact lobbying on the issue.

Corker said it was all a misunderstanding with which he was familiar because Tillerson called him about his problems with the sanctions bill.

The chairman said Tillerson’s problem was that American sanctions and European sanctions were different, and that while Exxon Mobil ongoing operations in Russia were allowed to continue, the wording of the American sanctions made it more difficult to manage the operations, which were allowed. Also, it would have made it more difficult to protect the safety of the 500 personnel working on the projects.

All Tillerson wanted was for the American sanctions to match the wording in the European Union sanctions, Corker said.

“It was not to lobby against the sanctions, but to point out that the Europeans were doing it in a much better way,” he said.

Corker said he plans on checking with his committee members about timing a vote on the Tillerson confirmation, which could come as early as next week.