WASHINGTON (NewsNation) — Sen. Dianne Feinstein, D-Calif., one of the longest-serving lawmakers in our nation’s history, died in her Washington, D.C. home at 90 years old. The announcement of her death comes a day after the California senator voted on the Senate floor.

Feinstein, the oldest sitting U.S. senator, was a passionate advocate for liberal priorities important to her state — including environmental protection, reproductive rights and gun control — but was also known as a pragmatic lawmaker who reached out to Republicans and sought middle ground.

Feinstein started her political career in the 1960s in San Francisco, where she served three terms as the city’s first female mayor. Since then, the career politician served six terms as California’s senior senator since 1992. She was one of several trailblazing women elected to Congress that year.

House Rules Committee Chair Tom Cole, R-Okla., announced unconfirmed reports of the passing of Feinstein at Friday morning’s meeting. He asked for a moment of silence.

Feinstein’s passing has garnered bipartisan reaction from members of Congress.

Senate Majority Leader Chuck Schumer, D-N.Y. teared up on the Senate floor as he gave a heartfelt tribute.

“Her integrity was a diamond. Her integrity shown like a beacon across the Senate and across the country,” Schumer said. “Dianne Feinstein was not like the others, she was in a class of her own.”

Senate Minority Leader Mitch McConnell, R-Ky., also spoke on the Senate floor, becoming emotional as he remembered Feinstein as “a truly remarkable individual.”

Sen. Thom Tillis, R-N.C., also offered his condolences, saying, “She was one of the most effective legislators in recent memory because of her willingness to work across the aisle in good faith in order to solve complex problems.”

Calif. Gov. Gavin Newsom, who will appoint her interim successor, released a statement on Feinstein’s passing. In it, the governor boasts about Feinstein’s leadership and effectiveness.

“She broke down barriers and glass ceilings but never lost her belief in the spirit of political cooperation. She was a fighter,” Newsom said.

She was elected to the San Francisco Board of Supervisors in 1969 and became its first female president in 1978, the same year Mayor George Moscone was gunned down alongside Supervisor Harvey Milk at City Hall by Dan White, a disgruntled former supervisor. Feinstein found Milk’s body.

It was a pivotal moment in Feinstein’s political career. She succeeded Moscone and became San Francisco’s first female mayor.

In the Senate, she was one of California’s first two female senators, the first woman to head the Senate Intelligence Committee and the first woman to serve as the Judiciary Committee’s top Democrat.

Although Feinstein was not always embraced by the feminist movement, her experiences colored her outlook throughout her five decades in politics.

A fierce debater who did not suffer fools, the California senator was long known for her verbal zingers and sharp comebacks when challenged on the issues about which she was most fervent. But she lost that edge in her later years in the Senate, as her health visibly declined and she often became confused when answering questions or speaking publicly.

In February 2023, she said she would not run for a sixth term the next year. And within weeks of that announcement, she was absent from the Senate for more than two months as she recovered from a bout of shingles.

Amid the concerns about her health, Feinstein stepped down as the top Democrat on the Judiciary panel after the 2020 elections, just as her party was about to take the majority.

In 2023, she said she would not serve as the Senate president pro tempore, or the most senior member of the majority party, even though she was in line to do so. The president pro tempore opens the Senate every day and holds other ceremonial duties.

Before her passing, there had been a very tough primary that was playing out for her seat next year. Many critics feared that if Newsom had to choose an interim choice, that it could affect the course of the race.

However, Newsom said he would not select any of the candidates running to replace Feinstein.

One of Feinstein’s most significant legislative accomplishments was early in her career, when the Senate approved her amendment to ban manufacturing and sales of certain types of assault weapons as part of a crime bill that President Bill Clinton signed into law in 1994. Though the assault weapons ban expired 10 years later and was never renewed or replaced, it was a poignant win after her career had been significantly shaped by gun violence.

This is a developing breaking news story. Check back for more updates.

The Associated Press contributed to this report.