The rough transcript of a telephone call where Donald Trump urged the Ukrainian president to investigate his political rival Joe Biden missed out key details, a senior White House official has reportedly told the impeachment inquiry.

The official, the US Army officer Alexander Vindman, said that Mr Trump had brought up tapes of Mr Biden discussing Ukrainian corruption on the call, but that the comment did not appear in a transcript later released to the public.

Mr Vindman also reportedly said that Volodymyr Zelenskiy, the Ukrainian president, made explicit mention of the Ukrainian company which Mr Biden’s son worked for but that again the comment was not in the transcript.

Mr Vindman’s testimony was given behind closed doors to the three congressional committees leading the impeachment probe on Tuesday but extracts have been widely reported by US media outlets.

His claims have drawn interest because the July 25 call in question lies at the heart of attempts by Democrats to formally kick Mr Trump from office through impeachment.