US President Donald Trump's impeachment trial has opened in the Senate, with the formal charges being read out ahead of the swearing in of all 100 senators as jurors.
The Senate's sergeant at arms called the proceedings to order and seven lawmakers prosecuting the charges, led by Adam Schiff of the Intelligence Committee and Jerrold Nadler of the Judiciary Committee, made the solemn walk across the US Capitol in Washington DC for a second day.
Senators filled the chamber, sitting silently at their seats under strict trial rules that prohibit talking or phones, as the ceremonial protocol shifted the proceedings out of Speaker Nancy Pelosi's Democratic-run House to the Republican-majority Senate.
"With the permission of the Senate, I will now read the articles of impeachment," Schiff said on Thursday, standing at a lectern in the well of the chamber, a space usually reserved for senators.
All eyes were on him.
"House Resolution 755 Impeaching Donald John Trump, president of the United States, for high crimes and misdemeanors," he began, reading the nine pages.
The other House prosecutors stood in a row to his side.
Later on Thursday afternoon, Chief Justice John Roberts is to administer the jurors' oath to senators who swear to deliver "impartial justice".
An escort committee of senators has been assigned to meet the judge at the Capitol.
The events, unfolding during an election year as Trump seeks another term, will be a test not only of his presidency but also of the nation's three branches of power and its system of checks and balances.
Several senators are running for the Democratic party's nomination to challenge Trump in November.
The president calls the impeachment a "hoax," even as new information emerges about his actions toward Ukraine that led to the charges against him.
Pelosi said new allegations from an indicted associate of Trump lawyer Rudy Giuliani, Lev Parnas, only reinforce the need for the Senate to consider further testimony about the president's actions toward Ukraine.
Pelosi noted that typically a special prosecutor would investigate but she doubted that would happen.
"This is an example of all of the president's henchmen," Pelosi said, "and I hope that the senators do not become part of the president's henchmen."
Trump faces a charge that he abused his presidential power by pressuring Ukraine to investigate Democratic rival Joe Biden, using military aid to the country as leverage.
Trump was also charged with obstructing Congress's ensuing probe.
Ahead of the proceedings, the Government Accountability office said the White House violated federal law in withholding the security assistance to Ukraine, which shares a border with hostile Russia.