Donald Trump was overheard discussing investigations requested of Ukraine in a phone call with a US ambassador, impeachment investigators have been told.

David Holmes, a political counsellor at the US Embassy in Kiev, is giving evidence at the inquiry into whether the US president wrongly held up military aid to Ukraine until it committed to investigating his Democratic political rival Joe Biden.

Mr Holmes says he was at a lunch in Kiev on July 26 with Ambassador Gordon Sondland and others when Mr Sondland spoke to the president on his mobile phone.

Donald Trump
President Donald Trump stands accused of asking Ukraine to investigate his rivals (Evan Vucci/AP)

Mr Holmes said he overheard Mr Sondland talking with Mr Trump about Ukrainian President Volodymyr Zelenskiy because Mr Trump’s voice was loud.

He said he overheard the president ask about “doing the investigation”, and Mr Sondland told him Mr Zelenskiy would do it and would do “anything you ask him to”.

Mr Holmes said he asked Mr Sondland if it was true that Mr Trump did not care about Ukraine. He said Mr Sondland replied the president only cared about the “big stuff”, and the “big stuff” included the Biden investigation.

Mr Sondland has said he had no recollection of having discussed the Bidens with Mr Holmes.

Mr Trump tweeted during Mr Holmes’s testimony that he has never been able to overhear anyone talking through a phone. He said: “I’ve even tried, but to no avail. Try it live!”

Mr Holmes also expressed concern about the role of Rudy Giuliani in Ukraine policy.

He says he recognised last spring that the Kiev embassy’s priorities had become overshadowed by a political agenda driven by Mr Giuliani – who is Mr Trump’s personal lawyer, “and a cadre of officials operating with a direct channel to the White House”.

He said that cadre included Mr Sondland, Energy Secretary Rick Perry and Ukraine envoy Kurt Volker. The group referred to itself as “The Three Amigos”.

The campaign by Mr Giuliani involved public statements attacking the ambassador to Ukraine, Marie Yovanovitch, as well as a push for Ukraine to investigate interference in the 2016 presidential election and the Bidens.

Fiona Hill and David Holmes
Fiona Hill and David Holmes are sworn in to testify before the House Intelligence Committee (J Scott Applewhite/AP)

Also giving evidence to the impeachment inquiry on Thursday is Fiona Hill, a former White House analyst on Russia.

She has denounced as “fictional” the contention from some Republicans that Ukraine interfered in the 2016 US election.

In prepared opening remarks to the House Intelligence Committee, she also urged politicians not to “promote politically-driven falsehoods that so clearly advance Russian interests”.

She added: “I have no interest in advancing the outcome of your inquiry in any particular direction, except toward the truth.”