Sen. Elizabeth Warren was silenced by her Republican colleagues Tuesday for "impugning the motives" of Sen. Jeff Sessions, nominated for attorney general.

Warren had been holding the Senate floor, the night before Sessions was expected to be confirmed. She began reading a 1986 letter from Coretta Scott King, the widow of Martin Luther King Jr., that expressed opposition to Sessions' nomination to be a federal judge. Sessions had been an attorney in Alabama at the time.

"Mr. Sessions has used the awesome power of his office to chill the free exercise of the vote by black citizens," King wrote in the letter.

Senate Majority Leader Mitch McConnell interrupted Warren, saying she had violated Rule XIX and "impugned the motives and conduct of our colleague from Alabama." The Senate then voted to not allow Warren to finish speaking. McConnell said Warren had been warned about violating the rule. "She was given an explanation. Nevertheless, she persisted," he said.

Senate Democrats and others, including Hillary Clinton, took to Twitter to show their disapproval of the decision to silence Warren. Many used the hashtag #LetLizSpeak.

Warren took to social media herself and read the letter on Facebook live.