(CNN) The Senate on Wednesday confirmed Brian Benczkowski to lead the Justice Department's criminal division on a near party-line vote over Democratic objections to his nomination due to ties to a prominent Russian bank.

The Senate confirmed Benczkowski 51-48. Sen. Joe Manchin of West Virginia was the only Democrat to vote yes.

Benczkowski's nomination was controversial because of his work for Alfa Bank, which has been scrutinized by FBI counterintelligence. Benczkowski, a former lead staffer to Attorney General Jeff Sessions in the Senate and a Trump transition official, has faced criticism from Democrats since he was nominated last year over his past private-practice work on behalf of Alfa Bank, one of Russia's largest financial institutions.

All 10 Democrats on the Senate Judiciary Committee in May called on President Donald Trump to pull his nomination.

In a statement Tuesday night, Sen. Dianne Feinstein, the top Democrat on the Judiciary Committee, lamented Benczkowski's refusal to recuse himself permanently from matters involving the ongoing Mueller probe, saying his nomination presented "glaring conflicts of interest."

Sen. Dick Durbin, the Senate's No. 2 Democrat, said in a tweet Tuesday that "the warning signs are clear" about Benczkowski. And Sen. Sheldon Whitehouse, a Rhode Island Democrat, in a floor speech called out his "astoundingly weak qualifications," positing that Benczkowski's close ties to Sessions and the administration could be leveraged to stymie the ongoing Mueller probe or create a backchannel for improper information sharing.

Questions surrounding Alfa Bank first arose in 2016 when a group of computer scientists raised concerns about Internet records that showed that Alfa Bank servers repeatedly looked up the unique internet address of a Trump Organization computer server in the United States. Authorities never alleged any wrongdoing, and Alfa Bank denied any misconduct.

Benczkowski was nominated last year and was voted out of committee along party lines, but a Senate floor vote to confirm him lingered for months.

At his confirmation hearing last year, Benczkowski said he would initially recuse himself from anything involving Alfa Bank.

"I would be recused from any matter involving Alfa Bank for the first two years of my tenure in the department if I'm fortunate enough to be confirmed," Benczkowski said. "With respect to this particular matter, this investigation that we conducted for Alfa Bank, if the subject matter of that investigation in some way comes before me in the criminal division at any point in my tenure I want to be clear, I will recuse from that completely."

Sessions applauded the confirmation in a statement issued after the vote, calling Benczkowski an "outstanding lawyer" and citing his years of service at the Justice Department.

"This will be the sixth senior position Brian has held at the Department, and we are fortunate to have someone with his breadth of experience and strong leadership skills willing to serve again," Sessions said. "At a time like this —with surging violent crime and an unprecedented drug epidemic — this position is especially important."

This story has been updated to include additional developments.