The Republican-controlled U.S. Senate voted early on Wednesday on party lines to approve the rules for President Donald Trump's impeachment trial, rejecting Democratic efforts to obtain evidence and ensure witnesses are heard.

The U.S. Senate voted early on Wednesday to approve rules governing the impeachment trial of President Donald Trump, including delaying a debate over whether to call witnesses until the middle of the trial.

The Republican-controlled U.S. Senate blocked Democratic attempts on Tuesday to obtain evidence and call a witness in President Donald Trump's impeachment trial, an early sign the proceeding could advance on lines favorable to Trump.

Bernie Sanders scrapped Iowa campaign appearances, Amy Klobuchar sent campaign representatives to "hot dish" dinners and Elizabeth Warren planned a remote video speech as the Democratic U.S. senators running for president got stuck in Washington for Donald Trump's impeachment trial.

The Republican-controlled U.S. Senate rejected Democratic efforts on Tuesday to obtain evidence and call witnesses in President Donald Trump's impeachment trial, an early sign the proceeding could advance along lines favorable to Trump.