The lawyer said Trump denied a request to provide evidence from House prosecutors, saying the impeachment was "unconstitutional".

"The president will not testify at an unconstitutional trial," Jason Miller, an adviser to former US President Donald Trump, said on Wednesday.

The remarks came after Democratic congressman Jamie Raskin, who headed the impeachment resolution group against Trump, sent a letter to the former US president inviting him to take the oath of testimony during the trial.

Trump's group of lawyers quickly responded, saying that this was just a "public relations trick".

Many senators believe that Trump testifying in court is a bad idea.

The US Senate will begin the impeachment trial of Trump on February 9, after receiving a clause accusing him of "inciting riot" from the House of Representatives.

Many Republicans argued that the trial would serve no other purpose than to divide the country more, accusing Democrats of simply wanting to score political points and getting the final shot against Trump.