The Senate confirmed President Trump's nominee to lead the Justice Department's Criminal Division despite concerns about his ties to a bank that has come under scrutiny by the FBI.

Senators voted 51-48 to approve Brian Benczkowski to be an assistant attorney general. Sen. Joe Manchin (D-W.Va.) was the only Democratic senator to support the nomination.

Benczkowski was first nominated more than a year ago, in June 2017. He was renominated in January after his nomination was bounced back to the White House at the end of last year.

Benczkowski's nomination had stalled amid questions about his work at Alfa Bank, a Russian bank that has faced scrutiny in the federal investigation into Moscow's influence on the 2016 presidential election.

Democrats have pounced on the selection of Benczkowski, saying it's an attack on special counsel Robert Mueller's investigation as he probes Russian election interference and potential collusion between the Trump campaign and Moscow.

"I cannot believe the Republican Party just rubber-stamped a nominee to head the Justice Department's Criminal Division who has no prosecutorial experience, who chose to represent a Russian bank with deep ties to [Russian President] Vladimir Putin, and who would not commit to recuse himself from Russia-related matters if confirmed.This could prove to be a historic mistake," said Sen. Dick Durbin (Ill.), the No. 2 Senate Democrat.

Sen. Dianne Feinstein (Calif.), the top Democrat on the Judiciary Committee, also questioned if Benczkowski would give Attorney General Jeff Sessions insight into the investigation, from which he recused himself from last year.

"Benczkowski's close ties to Attorney General Sessions raise serious questions as to whether he would serve as a backdoor allowing the Attorney General to see into the investigation," she said in a statement.

Benczkowski disclosed to lawmakers last year that he used to represent Afla Bank, one of Russia's largest financial institutions, according to The New York Times.

Benczkowski said in a letter, which was obtained by the Times, that he was initially unable to reveal his former work because of a confidentiality agreement.

The FBI investigated Alfa Bank after it found that one of the servers linked to the bank was communicating with a server tied to the Trump Organization. The FBI later found that the communications were not between the Trump campaign and Russia, according to the Times.

Because nominations only need a majority support, Trump's picks can clear the Senate without any help from Democrats.

Republicans had praised Benczkowski ahead of Wednesday's vote.

"His resume includes distinguished service in five different leadership positions at the Department of Justice under three Attorneys General. ... His nomination has won praise from a number of former Justice Department officials who served under presidents of both parties," Senate Majority Leader Mitch McConnell (R-Ky.) said.