A US diplomat has revised the evidence he previously gave to a congressional impeachment investigation into President Donald Trump.
Gordon Sondland has acknowledged what Democrats in the House of Representatives contend was a clear quid pro quo, pushed by Mr Trump and his personal lawyer, Rudy Giuliani, with Ukraine.
Mr Sondland, in an addendum to his sworn earlier testimony, said that military assistance to America's East European ally was being withheld until Ukraine's new president agreed to release a statement about fighting corruption as Mr Trump wanted.
Mr Sondland said he knows that proposed arrangement to be a fact because he was the one who carried the message to a Ukrainian official on the sidelines of a conference in Warsaw with vice president Mike Pence.
Mr Sondland recalled: "I said that resumption of US aid would likely not occur until Ukraine provided the public anti-corruption statement that we had been discussing for many weeks."
His three-page update, tucked beneath hundreds of pages of sworn evidence from Mr Sondland and former Ukraine special envoy Kurt Volker, was released by House investigators as Democrats prepared to push the closed-door sessions to public hearings as soon as next week.
Mr Trump has denied any quid pro quo, but Democrats say there is a singular narrative developing since the president's July 25 call with Ukrainian President Volodymyr Zelenskiy when he first asked for "a favour".
That request, which sparked the impeachment inquiry, included a public investigation into Ukrainian activities by Democratic former vice president Joe Biden and his son and Mr Trump's allegations of Ukrainian interference in the 2016 US election.
On Wednesday, the State Department's third-ranking official is expected to tell Congress that political considerations were behind the agency's refusal to deliver a robust defence of the former US ambassador to Ukraine.
People familiar with the matter say David Hale plans to tell congressional impeachment investigators that secretary of state Mike Pompeo and other senior officials determined that defending ambassador Marie Yovanovitch would hurt the effort to free up US military assistance to Ukraine.
Adam Schiff, the chairman of the Intelligence Committee, said the House panels conducting the inquiry are releasing the word-by-word transcripts of the past weeks' closed-door hearings so the American public can decide for themselves.
"This is about more than just one call," Mr Schiff wrote in an op-ed in USA Today. "We now know that the call was just one piece of a larger operation to redirect our foreign policy to benefit Donald Trump's personal and political interests, not the national interest."
White House press secretary Stephanie Grisham issued a statement saying the transcripts "show there is even less evidence for this illegitimate impeachment sham than previously thought".
In the transcripts and accompanying cache of text messages, US diplomats are shown trying to navigate the demands of Mr Trump and his personal lawyer, Rudy Giuliani, who they soon learn is running a back-channel US foreign policy on Ukraine.
"It kept getting more insidious," Mr Sondland told investigators, as the "timeline went on".
Testimony from Sondland and Volker demonstrates:
➡️Trump used a White House meeting and military aid to pressure Ukraine to publicly announce political investigations.
➡️The pressure campaign came at the expense of our national security.
➡️And it got more insidious over time. pic.twitter.com/NMZt2XRHDk
— Adam Schiff (@RepAdamSchiff) November 5, 2019
Mr Sondland testified that he spoke with Mr Pompeo about Mr Giuliani, "and Pompeo rolled his eyes and said: 'Yes, it's something we have to deal with.'"
In his revised evidence, Mr Sondland, a wealthy businessman who donated 1 million US dollars to Mr Trump's inauguration, says his memory was refreshed by the opening statements of two other inquiry witnesses, the top US diplomat in Ukraine, William Taylor, and Tim Morrison, a European expert at the National Security Council.
In his initial evidence on October 17 the ambassador said he did not "recall taking part in any effort to encourage an investigation into the Bidens". He told investigators he did not know that the Ukraine firm Burisma, that Mr Trump wanted Ukraine to investigate, was linked to Mr Biden's son Hunter.