US Secretary of State Mike Pompeo has confirmed he was listening in as the president asked Ukraine to investigate a political opponent.

Axar.az reports citing BBC.

The call - between Donald Trump and President Volodymyr Zelensky - is at the centre of a Democratic impeachment inquiry against Donald Trump.

Mr Pompeo dodged questions about the call in an interview just days ago.

President Trump denies improperly pressuring Ukraine and has accused opponents of mounting a "coup".

During the conversation, which triggered a whistleblower's formal complaint, the US president asked Mr Zelensky to investigate Democratic rival Joe Biden and his son Hunter.

Mr Pompeo's admission during a news conference in Italy came after media reported he was party to the conversation as well. "I was on the phone call," Mr Pompeo said.

He did not directly answer a question on whether anything in the phone call alarmed him, but said it had focused on US policy with Ukraine.