A top US diplomat has told an impeachment inquiry that he followed President Donald Trump's orders to put pressure on Ukraine to investigate his Democratic rival Joe Biden.
Ambassador Gordon Sondland said the instruction came from Mr Trump's personal lawyer Rudy Giuliani.The inquiry is assessing if Mr Trump withheld military aid to Ukraine as a precondition. He denies any wrongdoing.
It is illegal in the US to seek foreign help to gain electoral advantage.
Mr Biden is one of top contenders for the Democratic nomination for the 2020 presidential election.
Mr Sondland, the US ambassador to the EU, told the latest hearing in the US House of Representatives that Mr Giuliani had sought a public statement from Ukraine's leader Volodymyr Zelensky announcing a probe into "corruption issues".
Mr Giuliani specifically mentioned the company Burisma - which had the son of Democratic presidential candidate Mr Biden, Hunter, as a board member - and issues surrounding the 2016 US presidential election, he said.
If found guilty in a majority vote in the House, Mr Trump will face an impeachment trial in the Senate. But two-thirds of members of that Republican-controlled chamber would then need to vote for Mr Trump to be removed from office.
What exactly did Sondland say?
In his opening statement, Mr Sondland said he had worked with Mr Giuliani "at the express direction of the president". While he is the US ambassador to the EU, Mr Sondland said his brief included work on Ukraine alongside other colleagues - despite that country not being an EU member.
"We did not want to work with Mr Giuliani. Simply put, we played the hand we were dealt. We all understood that if we refused to work with Mr Giuliani, we would lose an important opportunity to cement relations between the United States and Ukraine. So we followed the president's orders," he added.
He then confirmed that the president had sought an investigation in exchange for a White House visit for Mr Zelensky - a quid pro quo, meaning a favour in return for a favour.
"I know that members of this committee have frequently framed these complicated issues in the form of a simple question: Was there a quid pro quo? As I testified previously, with regard to the requested White House call and White House meeting, the answer is yes."
However, Mr Sondland also said he had never directly heard from the president that military aid would be released in exchange for such a probe.
The US diplomat said he was "adamantly opposed" to the suspension of military aid to Ukraine, and was never told why it was withheld.
But he came to believe it was linked with Ukraine announcing corruption investigations.
Mr Sondland said he later told an aide to the Ukrainian president: "I believed that the resumption of US aid would likely not occur until Ukraine took some kind of action on the public statement that we had been discussing for many weeks."
Moreover, the ambassador insisted that this was not a secret plan, as some critics have suggested, instead arguing it was transparent and that his superiors were "fully supportive".