(CNN)President Joe Biden said Thursday that he's done a "deep dive" on four potential candidates to succeed Justice Stephen Breyer on the US Supreme Court, but he declined to name any of the prospective nominees.

       "I've taken about four people and done the deep dive on them, meaning thorough background checks, to see if there's anything in the background that would make them not qualified," Biden told NBC News' Lester Holt in an interview taped Thursday.

       The White House this week indicated that Biden remains on track to select a nominee before his self-imposed end-of-February deadline. The President has said he plans to nominate a Black woman to the high court, which would be a historic first.

       DC Circuit Judge Ketanji Brown Jackson, California Supreme Court Justice Leondra Kruger and South Carolina US District Court Judge J. Michelle Childs have been widely viewed as an early short list.

       White House officials have begun reaching out to potential candidates to gather more information about their records. And, as part of the vetting process, the FBI has contacted friends and former colleagues of potential nominees. A senior administration source told CNN earlier this week that there had been no in-person meetings between candidates and White House staff yet, and that some interactions with staff are likely to be over the phone.

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       Daily strategy meetings inside the West Wing are also underway as Biden has spent several evenings in the residence reviewing binders related to past cases of potential picks.

       "As he's looking at the process, he's reviewing not just bios, but he's also reviewing cases and he is looking at binders of cases, because he is ... taking this approach very seriously. He's taking a very thorough approach to it," White House press secretary Jen Psaki told reporters Tuesday.

       The President, in his NBC News interview, remained optimistic about garnering the support of Senate Republicans, saying, "I'm not looking to make an ideological choice here. I'm looking for someone to replace Judge Breyer with the same kind of capacity Judge Breyer had, with an open mind, who understands the Constitution, interprets it in a way that is consistent with the mainstream interpretation of the Constitution." He also stated that the short list of nominees are "incredibly well-qualified."

       On Thursday evening, Biden met with Democrats on the Senate Judiciary Committee -- which will handle the nominee's confirmation -- to discuss who he should choose. And earlier Thursday, the White House Counsel's Office called Utah Republican Sen. Mitt Romney to discuss his views of the Supreme Court vacancy, a follow-up on a conversation he'd had with Biden earlier this week. Romney told CNN that no names were discussed in either call. But he conveyed his desire to have a candidate who could garner bipartisan support.

       Following the meeting, Senate Judiciary Chairman Dick Durbin of Illinois told reporters that he and his Democratic colleagues had shared with the President their own Supreme Court nominee recommendations, and that their message to Biden was that they trust him.

       "His decision to appoint a Black woman to the Supreme Court is literally going to change the face of the court for the future for our history in the United States. We understand that responsibility. We shared with him some of our recommendations. But mainly the message was we trust your judgment, Joe Biden, when it comes to choosing the right person," Durbin said.

       He added: "I'd say the mood of the meeting was half friendly and light, the other half very serious."

       Durbin also said that he believes Biden will meet with nominees "soon." Durbin did not have any specific names or a number of women being considered.

       "He's going to take up meeting with the nominee soon and we encouraged him to do it the right way," Durbin said. He would not elaborate on the definition of "soon."

       Durbin and the top Republican on the committee, Sen. Chuck Grassley of Iowa, met with Biden at the White House last week about the pick. The President has also spoken with Senate Republican Leader Mitch McConnell of Kentucky over the phone regarding the Supreme Court vacancy.

       This story has been updated with additional information.

       CNN's Betsy Klein, Kaitlan Collins, Phil Mattingly and Manu Raju contributed to this report.