Rod Rosenstein, the pick for the No. 2 position at the Justice Department, said Tuesday that he was not aware of any requirement that he recuse himself from a federal investigation into Russian interference in the presidential election.

But he said he was open to appointing a special counsel to look into the matter if he ultimately determined it appropriate.

Rosenstein, the longtime United States attorney for Maryland and nominee for deputy attorney general, appeared before the Senate Judiciary Committee on Tuesday for a confirmation hearing that focused largely on how he would oversee any probe involving the Trump campaign and Russian meddling.

Attorney General Jeff Sessions recused himself last week from any investigations touching the Trump campaign following revelations of his undisclosed contacts with the Russian ambassador. That move means the Russia inquiry would be under Rosenstein’s watch.

Under questioning from senators, Rosenstein would not commit to recusing himself. He said he was not familiar with the facts of any investigation and was unaware of any requirement that he abandon oversight. But he said he would recuse if it was necessary.

Democrats have demanded that Rosenstein, who as deputy attorney general would have day-to-day oversight of Justice Department operations, step aside.

“I will use every possible tool to block the nomination of Rod Rosenstein to be deputy attorney general unless he commits to appoint independent special prosecutor,” Sen. Richard Blumenthal, a Connecticut Democrat and Judiciary Committee member, said in a statement.

Appearing on CNN’s “New Day” program Tuesday, Blumenthal said in advance of the hearing that he would confront Rosenstein about whether he’d be willing to seek a special prosecutor. “I’m going to put it to him very directly that he has an obligation as the deputy, that only he can do it,” the senator said, “so it falls to him.”

Sen. Dianne Feinstein of California, the committee’s top Democrat, added: “We need steel spines, not weak knees, when it comes to political independence in the Department of Justice.”

But committee chairman, Charles Grassley of Iowa, said such calls were premature and that the appointment of a special counsel was not the best way to ensure transparency.

“There is no mandatory public report or other finding at the end of the investigation if no charges are filed. The investigations can just disappear without the public ever understanding what the facts were,” Grassley said in his prepared remarks.

Rosenstein was appointed U.S. attorney for Maryland in the George W. Bush administration and served in the job for the entire Obama administration.

Rachel Brand, another former Justice Department attorney, also faces a confirmation hearing Tuesday for the job of associate attorney general, the department’s No. 3 position.

(AP)