- Video report ITV News Washington Editor Robert Moore
Donald Trump has been charged with abuse of power and obstruction of Congress after a long-running impeachment investigation.
The US president stands accused of "high crimes and misdemeanours".
House Judiciary Committee Chairman Rep. Jerrold Nadler Mr Trump said no one "not even the President, is above the law".
He said: "Our president holds the ultimate public trust; when he betrays that trust and puts himself before country, he endangers the constitution, he endangers our democracy and he endangers our national security."
Mr Nadler said the was a clear path to challenge those who "so violate their oath of office", namely impeachment.
Mr Nadler said the first article was an abuse of power - which relates to Mr Trump asking Ukraine to investigate the business links of the son of Democratic 2020 White House rival Joe Biden.
He said the president had also been blocking the ongoing impeachment inquiry dating from the 2016 election - relating to alleged Russian interference.
Mr Nadler said the president "engaged in unprecedented, categorical and indiscriminate defiance" of that inquiry.
To that end, Mr Trump has also been charged with obstruction of Congress.
Ahead of the announcement, the president was busy firing off tweets, hitting out at current FBI director Christopher Wray and denouncing the calls to impeach him as "political madness".
Mr Trump went on the offensive after the Justice Department inspector general reported the investigation into Trump's campaign and alleged links to Russia was legitimate but also flawed.
Within minutes of the press conference wrapping up, Mr Trump was on Twitter once more, again insisting the Ukraine president had said "many, many times" there was no pressure from the White House to investigate the Bidens.
He also fired off one of his favourite descriptions of the whole impeachment process: "Witch hunt!"
House Intelligence committee chair Adam Schiff offered the evidence underlying the charges against the president.
Mr Schiff described impeaching the president - which he had been reluctant to do - as an “extraordinary remedy”.
However, he said: “The actions of President Trump gave Congress no alternative.
“We stand here today because the president’s continuing abuse of his power has left us no choice.
“To do nothing would make us ourselves complicit in the president’s abuse of his high office, the public trust and our national security.”
ITV News Washington Correspondent Robert Moore said the "grim, unsmiling faces" reflected the Democrats’ description of this as a "reluctant obligation".
He added that in both charges, Democrats "say they have identified a pattern of behaviour, not just singular acts".
Democratic leaders say Trump put his political interests above those of the nation when he asked Ukraine to investigate his rivals, including Democrat Joe Biden, and then withheld $400 million in military aid as the US ally faced an aggressive Russia.
They say he then tried obstructed Congress by stonewalling the House investigation.
The outcome, though, appears increasingly set as the House prepares for voting, as it has only three times in history against a US president.
Voting is expected in a matter of days in the Judiciary Committee and by Christmas in the full House.