The US Senate’s top Democrat has called for current and former White House aides to testify at President Donald Trump’s expected impeachment trial.
Chuck Schumer said he wanted senior officials including White House acting Chief of Staff Mick Mulvaney and ex-adviser John Bolton to be summoned.
But the Republicans, who control the Senate, have called for a short trial without witnesses.
A vote in the House to impeach Mr Trump is expected on 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 is also accused of obstructing Congress. The White House refused to allow staff to testify during hearings in the House of Representatives in recent weeks.
The Republican president denies wrongdoing. He has called the Democratic-led inquiry a “witch hunt” and predicted it will even benefit him in next year’s presidential election.
Mr Trump lashed out on Sunday at the Democratic leader of the US House of Representatives, Speaker Nancy Pelosi, tweeting that “Nancy’s teeth were falling out of her mouth, and she didn’t have time to think!”