President Donald Trump spoke with three more potential Supreme Court candidates on Tuesday as a key senator privately aired concerns about one of the contenders.

As Trump weighs his options, he has heard from Sen. Rand Paul, R-Ky., who has expressed reservations about one top potential nominee, Brett Kavanaugh, according to a person familiar with the call but not authorized to publicly disclose details of it. The activity around Kavanaugh was an early glimpse of the frenzied jockeying around the short list of candidates in the run-up to Trump's July 9 announcement.

With a narrow 51-49 GOP majority in the Senate, losing any Republican senator could begin to doom a nominee. Paul's objections echo those made by outside conservative groups over Kavanaugh, who is seen as a top contender for the vacancy but who activists warn is too much of an establishment-aligned choice.

Trump has said he'll choose his nominee from a list of 25 candidates vetted by conservative groups. Top contenders include federal appeals judges Kavanaugh, Raymond Kethledge, Amul Thapar and Amy Coney Barrett — all of whom spoke with Trump on Monday.

"These are very talented people, brilliant people," Trump said Tuesday during an appearance in West Virginia. "We're going to give you a great one."

The White House says Trump has spoken to seven candidates. There were the four interviews Monday, as well as a conversation with Republican Sen. Mike Lee of Utah, who is not regarded as a top contender but who is being pushed by key conservatives.

Trump has also spoken with Thomas Hardiman, who has served with Trump's sister on the 3rd U.S. Circuit Court of Appeals in Philadelphia, according to a person familiar with the conversation who also was not authorized to publicly discuss it.

Another candidate considered a top contender is Joan Larsen, who serves on the federal appeals court in Cincinnati.