US Senator Dianne Feinstein of California has asked to be temporarily replaced on the Judiciary Committee, shortly after two House Democrats called on her to resign after her extended absence from Washington.
In a statement on Wednesday, the long-serving Democrat said her recovery from a case of shingles had been delayed because of complications.
The 89-year-old - who is the oldest serving member of Congress - has been absent from Washington for about two months, taking out a key Democratic vote in a chamber where the party holds a narrow majority.
Ms Feinstein provided no date for her return to the Senate and said she had asked Majority Leader Chuck Schumer to ask the Senate to allow another Democrat to serve in her committee seat until she was able to return.
“I intend to return as soon as possible once my medical team advises that it’s safe for me to travel," she said in thestatement.
“In the meantime, I remain committed to the job and will continue to work from home in San Francisco.”
Her decision to seek a committee stand-in comes amid increasing anxiety within her party that her lengthy absence has damaged Democratic efforts to confirm President Joe Biden’s nominees for federal courts in a narrowly divided chamber.
California Representative Ro Khanna, one of two Democratic House members who called on Wednesday for Ms Feinstein to resign, said in a statement on Wednesday: “This is a moment of crisis for women's rights and voting rights. It's unacceptable to have Senator Feinstein miss vote after vote to confirm judges who will uphold reproductive rights.”
Democratic Representative Dean Phillips of Minnesota echoed Mr Khanna's sentiments on Twitter.
The long-serving Ms Feinstein, he wrote, “is a remarkable American whose contributions to our country are immeasurable".
"But I believe it’s now a dereliction of duty to remain in the Senate and a dereliction of duty for those who agree to remain quiet.”
The highly unusual challenge from Mr Khanna against a senior colleague from his own state and party comes amid the race to replace Ms Feinstein, who has announced that she will not seek re-election, opening up her seat for the first time in more than 30 years.
The senator has faced questions in recent years about her cognitive health and memory, though she has defended her effectiveness representing a state that is home to nearly 40 million people.
If Ms Feinstein decides to step down during her term, it would be up to Democratic Governor Gavin Newsom to fill the vacancy, potentially reordering the highly competitive race.
Ms Feinstein has had a groundbreaking political career and shattered gender barriers.
She was the first woman to serve as president of the San Francisco Board of Supervisors in the 1970s and the first female mayor of San Francisco.
In the Senate, she was the first woman to head the Senate Intelligence Committee and the first woman to serve as the Judiciary Committee’s top Democrat. She gained a reputation as a pragmatic centrist who left a mark on political battles over issues ranging from reproductive rights to environmental protection.
Agencies contributed to this report
