Presumptive Democratic presidential nominee Joe Biden may have whittled down his potential list of running mates to two top contenders, Sen. Kamala Harris, D-Calif., and former Obama National Security Adviser Susan Rice, according to an Axios report.

There has long been speculation that Harris and Rice were the frontrunners as Biden stated that he would choose a woman and both possible running mates have what many believe are the necessary qualifications for the role.

Harris, 55, is a top pick due to her prosecutorial skills, the report says. There are also some former members of the Obama and Clinton administration pushing for her candidacy. Prior to becoming California’s senator, she was the state’s attorney general from 2011 to 2017. She garnered national attention for her questioning of Supreme Court nominee Brett Kavanaugh in 2018, and has advocated for police reform after the death of George Floyd in May. Harris also has campaign experience after her run for the Democratic nomination, though she had clashed with Biden in debates.

Rice, 55, also has support from former members of the Obama administration, who believe her presence on the Biden ticket would mean the frequent appearance of both Barack and Michelle Obama on the campaign trail. During the Obama administration, Rice served as both national security adviser and U.S. ambassador to the United Nations. Rice may be targeted by Republicans due to her statements following the attack on a U.S. diplomatic facility in Benghazi, Libya in September 2012.

Rep. Susan Bass, D-Calif. is also in consideration, the Axios report noted, but her past statements on Cuba and Scientology have drawn some controversy.

Some of the other possible vice presidential picks for Biden include Sen. Tammy Duckworth, D-Ill., Sen. Elizabeth Warren, D-Mass., Rep. Val Demings, D-Fla., and Michigan Gov. Gretchen Whitmer. Atlanta Mayor Keisha Lance Bottoms and prominent Georgia politician Stacey Abrams have also been floated.

A SurveyUSA/FairVote poll provided to Vox on Wednesday shows Harris as the top pick among Democratic voters for the running-mate spot, followed by Warren and Rice.

Biden is not expected to announce his VP pick for another week or so. Recent general election polls show Biden with a strong lead over President Trump.