Former US president Donald Trump defence team on Thursday denied testifying in his looming impeachment trial and branded the process “unconstitutional,” after being called by House prosecutors to give evidence. 

Trump’s lawyers trashed the request in a letter by lead House prosecutor Jamie Raskin to answer questions over the January 6 attack on the US Capitol as a “public relations stunt.”

“Your letter only confirms what is known to everyone: you cannot prove your allegations” against Trump, attorneys Bruce Castor and David Schoen said in their reply.

Although the attorneys did not say whether he would testify, a senior advisor to Trump, Jason Miller, flat out said that the former president would not.

“The president will not testify in an unconstitutional proceeding,” Miller told AFP.

The refusal comes five days before the trial of the former US leader on one impeachment charge of “incitement to insurrection” opens in the US Senate.

ALSO READ | US House disciplines extremist Republican after QAnon storm

In his landmark second impeachment trial, Trump is accused of provoking the attack by his supporters on the US Capitol one month ago, halting the proceedings to certify opponent Joe Biden’s victory in the November presidential election.

Raskin had asked Trump, who has maintained without evidence that Biden won by massive fraud, to testify sometime next week, before or during the trial.

He said Trump, who now lives in his Florida Mar-a-Lago resort, had little excuse to avoid testifying, and could no longer claim he was too busy overseeing the country, as was the White House position when he was still president.

Raskin also warned that if Trump refused, it would be considered as supportive of the evidence against him.

“If you decline this invitation, we reserve any and all rights, including the right to establish at trial that your refusal to testify supports a strong adverse inference regarding your actions (and inaction) on January 6, 2021,” he added, AFP reported.

Raskin’s letter and the response set out the battle lines for the never-seen impeachment trial of a president after he has left office.

The Democratic House prosecutors, or impeachment managers, believe the Republican leader was “singularly responsible” for the Capitol attack, which left five dead.

“In a grievous betrayal of his oath of office, President Trump incited a violent mob to attack the United States Capitol,” they said, AFP reported.

However, Trump’s team argued in a filing Tuesday that whatever Trump said in the days and hours before the attack to encourage supporters to reject Biden’s election win amounted to constitutionally protected free speech.

And they declared it unconstitutional to put a former president on trial in the Senate.

The January 6 attack continues to haunt Washington and security has been at its peak. Prosecutors have charged some 180 people in the attacks, according to a tally by the George Washington University Program on extremism, and hundreds more are under investigation.

ALSO READ | Voting system producer files lawsuit against Fox News, Guiliani for defamation

The Justice Department has suggested they could build a case for seditious conspiracy by some Trump-supporting extreme right groups in the attack.

In a White House rally just hours before the attack, Trump encouraged supporters to reject the election results and to “fight like hell.”

While Democrats will make such statements the focus of their case, Trump’s lawyers will hone in on the question of constitutionality.

That could bring about his acquittal. Conviction requires the support of two-thirds of the 100 senators, who serve as judges and jury in the trial.

However, last week 45 of 50 Republican senators made clear in a vote they think trying an ex-president is unconstitutional.