Dianne Feinstein, the California senator who served for more than three decades and was a trailblazer for women in US politics, has died at age 90.
Ms. Feinstein was the oldest member of the US Senate and voted as recently as Thursday.
For months the veteran Democrat had faced questions about alleged memory and cognitive issues.
Ms. Feinstein was well known as a vocal advocate for gun control measures, and an ardent supporter of the assault weapons ban signed into law by President Bill Clinton in 1994.
In a statement, Ms Feinstein's office said she passed away at her home in Washington DC overnight.
California Governor Gavin Newsom must now appoint her replacement. He had previously vowed to nominate a black woman to serve out the remainder of her term, which ends in 2025.