The Senate backed the procedure proposed by Senate Majority Leader Mitch McConnell.

"53-47 [tally] Agreed to ... S. Res. 483; A resolution to provide for related procedures concerning the articles of impeachment against Donald John Trump, President of the United States," the Senate said.

According to the passed resolution, each sides will have 24 hours over three days — six days total — starting Wednesday afternoon to present their arguments, after which senators will have 16 hours to ask questions.

The upper chamber session started on Tuesday at 1:00 p.m. local time (18:00 GMT) and saw 11 Democratic-proposed amendments to obtain evidence and subpoena witnesses rejected before the trial rules were approved. However, the Senate is set to reconsider subpoenaing witnesses after these initial proceedings.

"We will not let the architects of the unfair House process convince the Senate to rewrite our rules just for President Trump," McConnell tweeted earlier on Wednesday.

Trump was impeached by the House of Representatives on December 18 on charges of abuse of power for pressuring Ukraine to investigate former Vice President Joe Biden over his alleged involvement in the corruption. Trump denies all accusations.