Video report by ITV News Washington Correspondent Robert Moore
President Donald Trump repeatedly prodded Ukraine's new leader to work with his personal legal team to investigate his political rival, a transcript of a call released by the White House has revealed.
Details of the conversation with the then newly-elected Ukrainian president, Volodymyr Zelenskiy, show Mr Trump tried to coerce him into an opening a probe into Joe Biden.
According to the transcript, Mr Trump said to the eastern European leader: "There's a lot of talk about Biden's son, that Biden stopped the prosecution and a lot of people want to find out about that."
In the US President's first solo press conference since the proceedings were brought against him, Trump defended the call, saying it was, "wonderful", "perfect" and "beautiful".
He also said that this phone call was the second with Mr Zelenskiy and that if the Democrats keep asking for it, he will release the first phone conversation.
The US president questioned the inquiry saying: "Impeachment? For that? When you have a wonderful meeting or a wonderful phone conversation?"
Washington papers show Mr Trump also said: "If you can look into it ... It sounds horrible to me," in reference to unsubstantiated allegations that Biden sought to interfere with a Ukrainian prosecutor's investigation of his son, Hunter.
Just days prior to the July 25 call, the White House had frozen nearly $400 million in aid to the Ukraine, a fact confirmed by Mr Trump during the call.
The release of the transcript is the central pillar of the formal impeachment inquiry launched earlier this week by House Speaker Nancy Pelosi.
President maintains stance of innocence amid release of documents
Mr Trump, the 45th President of the United States, has repeated stated he believes he has not done anything wrong.
Speaking to a meeting of foreign leaders on Wednesday, he said: "Just so you understand, it's the single greatest witch hunt in American history, probably in history."
Just minutes before the transcript was released, he tweeted: "Will the Democrats apologize after seeing what was said on the call with the Ukrainian President? They should, a perfect call - got them by surprise!"
In a previous tweet, Mr Trump had said: "Secretary of State Pompeo recieved permission from Ukraine Government to release the transcript of the telephone call I had with their President. They don’t know either what the big deal is. A total Witch Hunt Scam by the Democrats!"
Alongside his comments on Mr Biden, logs of the call show Mr Trump flippantly referring to the ex-FBI director as a "man named Robert Mueller" and says he turned in "a very poor performance," in reference to an investigation into wrongdoing during his election campaign.
The memo goes on to show the president made reference to the private cybersecurity firm that investigated Russia's hack of the Democratic National Committee servers during that campaign.
Mr Trump suggests that Ukraine may be in the possession of the email server, though it's unclear what he's referring to.
Trump also says he'd like to have his attorney general "call you or your people and I would like you to get to the bottom of it".