Former Vice-President Joe Biden is decrying reports that President Donald Trump urged the president of Ukraine to look into his son’s business dealings there.

Biden says in a statement that if the reports are true, “Then there is truly no bottom to President Trump’s willingness to abuse his power and abase our country.”

Biden said Trump should release the transcript of his July phone conversation with President Volodymyr Zelenskiy “so that the American people can judge for themselves.”

Biden released the statement after news organisations reported Trump had urged Zelenskiy to probe the activities of Biden’s son Hunter, who worked for a Ukrainian gas company.

The push to damage a political rival is at the heart of a whistleblower complaint that has created a showdown between Congress and the White House.

Two people familiar with the matter say the complaint was based on a series of events, one of which was a July 25 call between Trump and Zelenskiy.