Bill Taylor, the acting US ambassador to Ukraine, told impeachment hearings that President Trump directly asked about a Ukrainian investigation into his Democratic rival Joe Biden.
In previously unheard testimony, Bill Taylor said a member of his staff was told President Trump was preoccupied with pushing for a probe into Joe Biden.
The top diplomat was speaking at the first public hearings in the impeachment inquiry.
President Trump told reporters he did not recall making such comments.
The president is accused of withholding US military aid to Ukraine in order to pressure the country’s new president to publicly announce a corruption inquiry into Joe Biden, among the favorites to take him on in the 2020 presidential race.
President Trump denies any wrongdoing and has called the inquiry a “witch-hunt”.
During a detailed opening statement, Bill Taylor said a member of his staff had overheard a telephone call in which the president inquired about “the investigations” into Joe Biden.
The call was with US ambassador to the EU Gordon Sondland, who reportedly told the president over the phone that “the Ukrainians were ready to move forward”.
After the call, the staff member “asked ambassador Sondland what President Trump thought about Ukraine”, Bill Taylor said.
Bill Taylor said: “Ambassador Sondland responded that President Trump cares more about the investigations of Biden.”
When asked about Gordon Sondland earlier this month, the president had said: “I hardly know the gentleman.”
Responding to queries from reporters after the hearing, President Trump said: “I know nothing about that, first time I’ve heard it.”
He said he recalled Gordon Sondland’s testimony, in which the diplomat said he spoke to the president “for a brief moment” and President Trump had “said no quid pro quo under any circumstances”.
Gordon Sondland said he did not recall the phone call Bill Taylor described, “not even a little bit”, and “in any event it’s more second hand information”.
The impeachment inquiry has been going on for more than a month – but all previous hearings were private, with reports based on leaks and sources speaking to the media.
Today’s public hearings were the first time the public heard from witnesses directly and a chance for Democrats and Republicans to win over voters.