Trump impeachment: Schumer's case for White House witnesses
Senate Minority Leader Chuck Schumer delivered a press conference, calling for White House witnesses to testify at President Trump's expected impeachment trial.
Among those the Democrat wants summoned are White House acting Chief of Staff Mick Mulvaney and ex-National Security Adviser John Bolton.
But Republicans, who control the Senate, have called for a short trial without witnesses.
A vote in the Democratic-run House to impeach Mr Trump is expected to happen this Wednesday. If a majority votes for impeachment, the case will then move to a trial in the Republican-controlled Senate.
The president is accused of soliciting a foreign country to help him politically, by trying to pressure Ukraine to launch a corruption investigation into his Democratic rival Joe Biden. Mr Trump denies any wrongdoing.