ABC News says the network has obtained an audio recording that captures the moment Donald Trump told his associates to "get rid of" Marie Yovanovitch, who was then the US ambassador to Ukraine, before she was ousted amid efforts to pressure the country to investigate his political rivals, a charge at the heart of his impeachment trial.
The news outlet says the recording appears to include the president saying: "Get her out tomorrow. I don't care. Get her out tomorrow. Take her out. OK? Do it."
On the recording, Mr Trump is speaking at a small gathering that also included Lev Parnas and Igor Fruman, two business associates of Mr Trump's attorney Rudy Giuliani, who urged getting Ms Yovanovitch "out of the way" to advance a conspiracy investigation tying Joe Biden and his son Hunter to corruption in Ukraine.
Mr Fruman and Mr Parnas are facing federal indictments for their alleged role in a campaign finance fraud scheme using foreign money. They have pleaded not guilty.
Mr Parnas has since testified to members of Congress following the president's impeachment in the House, offering additional documents and testimony that further links Mr Trump to efforts to withhold aid to Ukraine in exchange for an investigation into the Bidens as 2020 election campaigns drew closer.
ABC says the recording was captured by Mr Fruman during a meeting on 30 April 2018 at the Trump International Hotel in Washington DC. The network reports that a copy of the recording is in the custody of federal prosecutors in New York.
Ms Yovanovitch was called back to the US in April 2019 following a State Department message urging her to leave Ukraine on the next possible plane. She later told congressional committees charged with investigating the president's impeachment that the decision was motivated by people with "questionable motives" with regards to Ukraine within the Trump administration.
The recording contradicts statements by the president and members of his administration that have denied Mr Trump's connection to Mr Fruman and Mr Parnas, despite several photos and videos capturing the men together and posing for photographs.
On the recording, Mr Parnas appears to say, according to ABC: "The biggest problem there, I think where we need to start is we gotta get rid of the ambassador. She's still left over from the Clinton administration ... She's basically walking around telling everybody 'Wait, he's gonna get impeached, just wait.'"
Ms Yovanovitch has served as a US diplomat with the State Department since Ronald Reagan's administration in the 1980s.
Records obtained by Congress from Mr Parnas show dozens of emails, WhatsApp messages and handwritten notes describing Mr Giuliani's attempts to facilitate a White House meeting with Ukrainian President Volodymyr Zelensky and to remove Ms Yovanovitch from her post.
One message showed that Mr Parnas and others were under order to perform "physical surveillance" on Ms Yovanovitch in Kiev.