President Donald Trump said on Monday he will announce his US Supreme Court pick by the end of the week, moving quickly to fill the seat of liberal icon Ruth Bader Ginsburg and cement a 6-3 conservative majority ahead of his November 3 re-election bid.

A day earlier, his Democratic challenger Joe Biden slammed Trump’s haste, and urged Republicans to oppose a confirmation vote before the election.

It takes four GOP senators breaking ranks to keep Trump’s nominee off the court.

“Uphold your constitutional duty, your conscience,” said Biden, speaking in Philadelphia on Sunday. “Let the people speak. Cool the flames that have engulfed our country.”

Jamming the nomination through, Biden said, would amount to an “abuse of power”.

The sudden vacancy is reshaping the presidential race, which to this point has been largely a referendum on how Trump had managed the Covid-19 pandemic.

Speaking on Fox News on Monday, Trump said he would put forward his nominee on Friday or Saturday and called upon the Republican-controlled Senate to vote on confirmation ahead of the election. “We have the presidency and the Senate and we have plenty of time,” Trump said, dismissing demands for making the nomination after the election. “I think that would be good for the Republican Party and I think it would be good for everybody to get it over with.”

Trump said he had a list of five finalists, “probably four”. He has mentioned two women as possible candidates: federal appellate judges Amy Coney Barrett and Barbara Lagoa. He appointed both to their current posts.

Ginsburg died on Friday of complications from pancreatic cancer at age 87. She is to lie in repose for public viewing at the Supreme Court on Wednesday and Thursday. She will be buried next week in Arlington.