The Senate impeachment trial of US President Donald Trump is likely to begin in seven days with key players sworn in later this week, Majority Leader Mitch McConnell said on Tuesday. Mr McConnell, a Republican senator from Kentucky, said he expected the House of Representatives to send the articles of impeachment against Mr Trump to the upper chamber on Wednesday. "We believe that if that happens -- in all likelihood -- we'll go through preliminary steps here this week which could well include the chief justice coming over and swearing in members of the Senate and some other kinds of housekeeping measures," Mr McConnell told reporters. "We hope to achieve that by consent which would set us up to begin the actual trial next Tuesday." He added that “all 53 of us have reached an agreement,” he said, referring to the Republican members in the Senate. Supreme Court Chief Justice John Roberts is to preside over the trial, with Mr Trump facing charges of abuse of power and obstruction of Congress. Mr McConnell's remarks came shortly after Nancy Pelosi, the Democratic House speaker, said Democrats would transmit the articles of impeachment to the Senate on Wednesday. "Tomorrow, we will transmit those articles & name impeachment managers. The Senate must choose between the Constitution & a cover-up," Ms Pelosi said in a tweeted statement. "The American people deserve the truth, and the Constitution demands a trial... The president and the senators will be held accountable," she added. Mr Trump will become only the third president in US history to go on trial in the Senate, risking his removal from office. Andrew Johnson was impeached in 1868 and Bill Clinton was impeached in 1998. It is highly unlikely Mr Trump will be removed from office, given Republicans' 53-47 control of the Senate, and the high two-thirds vote threshold required to find him guilty. It would require 14 GOP members to flip from party line and vote for Mr Trump’s impeachment. But both parties expect a tense two weeks or more of hearings that could lay bare the US leader's alleged wrongdoing to the American public on live television. Ms Pelosi attacked suggestions by Mr Trump and some of his supporters that the Senate, as soon as the trial opens, vote to dismiss the charges. That would only require a majority vote. She accused Mr McConnell of supporting the dismissal effort and called for him to agree to Democrat demands to subpoena witnesses and documents. The Senate majority leader "has signed on to a dismissal resolution. A dismissal is a cover-up," Ms Pelosi charged. Mr McConnell, however, pushed back against suggestions that he would try and prevent the trial from going ahead. "There's little or no sentiment for a motion to dismiss. We have an obligation to listen the arguments," he said. Trump was impeached on December 18 when the House voted to formally charge him with abusing his power by illicitly seeking help from Ukraine for his re-election campaign. He is accused of withholding aid to Ukraine to pressure Kiev to investigate former vice president Joe Biden, the frontrunner in the race for the Democratic party's 2020 presidential nomination. Mr Trump is also charged with obstruction for holding back witnesses and documents from the House impeachment investigation in defiance of Congressional subpoenas. Mr Trump has branded the case a "hoax" and a "witch hunt". Ms Pelosi had delayed delivering the articles of impeachment to pressure the Senate to agree to subpoena witnesses with direct knowledge of Trump's Ukraine actions, including his chief of staff Mick Mulvaney and former national security advisor John Bolton. Mr Bolton said on January 7 that he would be willing to testify if he is called into the Senate. But with Mr McConnell refusing to agree up front on the witness issue, Ms Pelosi decided to move ahead. The Senate trial is expected to last at least two weeks, depending on how the witness issue is ultimately decided. In 1999, the Senate trial that followed Mr Clinton's impeachment over the Lewinsky affair lasted five weeks. He was acquitted. That trial included ten days of testimony from witnesses.