President Donald Trump’s personal lawyer Rudy Giuliani has notified US politicians that he will not comply with a subpoena issued in the impeachment inquiry.

A letter sent by attorney Jon Sale says the subpoena is “overbroad, unduly burdensome, and seeks documents beyond the scope of legitimate inquiry”.

Mr Sale also echoes a letter from the White House counsel’s office in describing the impeachment inquiry itself as “unconstitutional” and “baseless”.

Democrats set a Wednesday deadline for Mr Giuliani to provide documents.

Text messages and witness testimony have revealed Mr Giuliani’s role in a back-channel effort to get Ukraine to investigate a gas company linked to the family of Democratic rival Joe Biden.

It was not immediately clear how House Democrats conducting the impeachment inquiry would respond to Mr Giuliani’s refusal to comply.