President Barack Obama has started to interview candidates for the U.S. Supreme Court to replace Justice Antonin Scalia, who died last month, National Public Radio reported on Tuesday, citing sources close to the process.

Among the interviewees are Chief Judge Merrick Garland of the U.S. Court of Appeals for the District of Columbia; Judge Sri Srinivasan of the same court; Judge Paul Watford of the 9th Circuit Court of Appeals based in San Francisco; Judge Jane Kelly of the 8th Circuit Court of Appeals based in St. Louis; and U.S. District Judge Ketanji Brown Jackson, who serves in Washington, D.C., NPR reported.

The first three of these individuals are considered the leading contenders, NPR said.

U.S. Attorney General Loretta Lynch earlier on Tuesday asked not to be considered as a nominee, the Justice Department said in a statement. Lynch had been rumored to be under consideration.

The process of filling the spot that was held by Scalia, one of the court's most conservative justices, has ignited a partisan battle in Washington.

Republicans who control the U.S. Senate do not want to see the court shift ideologically to the left and have said they will not hold a vote on Obama's nominee. All appointees by the president to the Supreme Court are subject to approval by the Senate.

Senate Majority Leader Mitch McConnell has said the next Supreme Court justice should be chosen by the winner of the Nov. 8 presidential election.