Former US vice president Mike Pence on Saturday said history would hold former president Donald Trump "accountable" for his role in the 2021 attack on the US Capitol, US media reported.

The remarks are likely to widen the rift between the former running mates, who have been at loggerheads ever since Pence refused to go along with Trump's efforts to overturn the 2020 election results and remain in power.

"President Trump was wrong," Pence said in a speech at the annual Gridiron Dinner in Washington, a white-tie gala put on by journalists that draws top politicians.

"I had no right to overturn the election. And his reckless words endangered my family and everyone at the Capitol that day. And I know that history will hold Donald Trump accountable," Pence was quoted as saying by multiple media.

Some of the thousands who stormed the US Capitol on January 6, 2021, called for Pence to be hanged, forcing him to scurry to a safe location.

Trump has already declared his intention to seek a new term as president in 2024 elections, and Pence indicated he may challenge him for the Republican nomination.

The Gridiron Dinner is usually a light-hearted event with skits and musical entertainment, and Pence initially sought to poke fun.

"I will wholeheartedly, unreservedly support the Republican nominee for president in 2024 -- if it's me," he said.

Pence's sharp remarks aimed at Trump were unexpected at the gala.

"Was at the dinner and can confirm @Mike_Pence definitely caught the room by surprise--lots of dropped jaws," tweeted Maryam Mujica, a former State Department official.