The 100 lawmakers of the US Senate were sworn in on Thursday as jurors for the impending impeachment trial of President Donald Trump.
Chief Justice of the Supreme Court John Roberts administered the oath to the senators to “do impartial justice”.
In the coming weeks, the senators will decide whether Mr Trump should be removed from office over charges brought by the House of Representatives.
The trial is scheduled to begin on 21 January.
Justice Roberts asked the senators, “Do you solemnly swear that in all things appertaining to the trial of the impeachment of Donald John Trump, President of the United States, now pending, you will do impartial justice according to the Constitution and the laws, so help you God?”
The lawmakers responded with “I do” before each signing in a book that they took the oath. Republican senate leader Mitch McConnell then adjourned the pre-trial proceedings and announced the trial would begin at 13:00 EST (18:00 GMT) on Tuesday.
Mr Trump is accused of abuse of power and obstruction of Congress. He has denied wrongdoing and branded the case against him as a “hoax”.