A police officer who defended the US Capitol during a riot by Donald Trump supporters on 6 January has said he feared he would be crushed by the mob.

"This is how I'm going to die," a tearful Aquilino Gonell told a Congressional committee as an inquiry opened into the Washington DC attack.

Another officer, Harry Dunn, who is black, said he was racially abused.

At least 535 rioters have been arrested since the attack that left five dead, including one police officer.

Prosecutors have so far secured only a few convictions.

The assault led to the political impeachment and acquittal of Republican Mr Trump, who was accused by lawmakers of inciting the riot - a claim he has repeatedly denied.

However, two Republicans - Liz Cheney and Adam Kinzinger - have broken ranks to join the investigation.

"If those responsible are not held accountable... this will remain a cancer on our constitutional republic," Ms Cheney said as the hearing began on Tuesday.

The select committee was formed after Republicans objected to an independent commission such as the one that investigated the 11 September 2001 attacks.

On Tuesday, four police officers described being beaten and assaulted by rioters who had come to disrupt the certification by Congress of President Joe Biden's election victory.

Officer Gonell described the scene as a "medieval battlefield".

Wiping away tears, he described returning home and pushing his wife away from him because of the amount of chemical irritant that had soaked into his uniform.

The Iraq War veteran went on to criticise Republicans for what he described as their "continuous shocking attempt" to "ignore or destroy the truth" about that day.

Asked by Ms Cheney about Mr Trump's claim that they were a "very loving crowd," Sgt Gonell hit back: "I'm still recovering from those hugs and kisses."

"If that was hugs and kisses, we should all go to his house and do the same thing to him."He later said that he did not mean for anyone to go to Mr Trump's home, and apologised for the "outburst".

Officer Dunn said he told several protesters that he had voted for Mr Biden.

"Does my vote not count? Am I nobody?" he told them, after they wrongly claimed that the election was fraudulent.

"That prompted a torrent of racial epithets," he testified. "One woman in a pink Maga [Make America Great Again] shirt yelled, 'You hear that, guys, this [expletive] voted for Joe Biden!"

"No-one had ever - ever - called me a [expletive] while wearing the uniform of a Capitol police officer."

Officer Michael Fanone slammed his fist on the desk as he accused Republicans of a "disgraceful" violation of their oaths of office.

Mr Kinzinger, one of the only Republicans who voted to impeach Mr Trump for his role in the riot, appeared to hold back tears as he criticised his colleagues.

"We still don't know exactly what happened. Why? Because many in my party have treated this as just another partisan fight. It's toxic and it's a disservice to the officers and their families," Mr Kinzinger said.

Officer Dunn said he did not fully process the racial comment until the following days.

"I was just trying to survive that day, and get home.

"When I was able to process it, it was so emotional. It was so disheartening and disappointing that we live in a country like that, where they attack you because of the colour of your skin.

"Just to hurt you. Those words are weapons."

Officer Daniel Hodges' lip trembled with emotion as he was shown a video of himself trapped in a doorway being pummelled by rioters, who he repeatedly referred to as "terrorists" during his testimony.

"To my perpetual confusion, I saw the Thin Blue Line flag, a symbol of support for police, more than once, as the terrorists continued to ignore our commands and attacked us," he said.