Washington, Feb 8 (IANS): Republican Senators voted to formally silence a Democratic colleague for impugning a peer, Senator Jeff Sessions of Alabama, by condemning his nomination for Attorney General by reading a letter by the widow of Martin Luther King Jr.

Democratic US Senator Elizabeth Warren had been holding forth on the Senate floor on Tuesday -- the eve of Sessions's expected confirmation vote -- reading from a 1986 letter by Coretta Scott King that criticised Sessions's record on civil rights, CNN reported.

Mitch McConnell, the Republican majority leader, said Warren had broken Senate rules by impugning the conduct of another Senator. In an extremely rare rebuke, she was instructed by the presiding officer to take her seat.

McConnell's objection to Warren's speech was put to a vote and Senators voted 49-43 in his favour.

Warren described the incident on Facebook: "During the debate on whether to make Jeff Sessions the next Attorney General, I tried to read a letter from Coretta Scott King on the floor of the Senate. The letter, from 30 years ago, urged the Senate to reject the nomination of Jeff Sessions to a federal judgeship. The Republicans took away my right to read this letter on the floor -- so I'm right outside, reading it now."

Coretta King's letter, according to the report, said that Sessions was unsuitable for that role because he had "used the awesome powers of his office in a shabby attempt to intimidate and frighten elderly black voters".

Sessions's nomination process has been dogged by reports that he attempted to suppress black voters when he was an attorney in Alabama.

The objection by McConnell raised the ire of Democrats and members of the public, many of whom shared the letter on social media using the hashtag #LetLizSpeak.

Bernice King, daughter of Coretta Scott King and Martin Luther King, wrote on Twitter: "Thank you @SenWarren for being the soul of the Senate during the #Sessions hearing. #LetCorettaSpeak #LetLizSpeak"

The Democratic National Committee said in a statement that it was a "sad day in America when the words of Martin Luther King Jr's widow are not allowed on the floor of the United States Senate".

Warren is now barred from speaking on the floor for the remainder of the debate, Mr McConnell's office said.

The debate is expected to conclude on Wednesday.