A supporter of US President Donald Trump holds a Confederate flag outside the Senate Chamber during a protest after breaching the US Capitol in Washington, DC, Jan 6, 2021. (SAUL LOEB / AFP)

US President-elect Joe Biden, politicians, civic leaders and activists criticized the police response to supporters of President Donald Trump who stormed the US Capitol, saying there was a more draconian response to Black Lives Matter protests months earlier.

One demonstrator carried a Confederate flag, long associated with white supremacy, through the building. Photos showed a noose attached to a wooden beam

"You can't tell me that if it had been a group of Black Lives Matter protesters … they wouldn't have been treated very differently than the mob of thugs that stormed the Capitol," Biden said, "We all know that is true. And it is totally unacceptable. Totally unacceptable."

He criticized the police response to the predominantly white mob on Thursday who breached the Congress building the day before, running riot through the symbol of US democracy.

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The Black Lives Matter Global Network Foundation said in a statement:

"When black people protest for our lives, we are all too often met by National Guard troops or police equipped with assault rifles, shields, tear gas and battle helmets.

"When white people attempt a coup, they are met by an underwhelming number of law enforcement personnel who act powerless to intervene, going so far as to pose for selfies with terrorists."

Biden compared how Wednesday's rioters were treated with the harsher tactics used on black and white demonstrators nationwide who took to the streets to call for an end to police brutality this summer following the killing of George Floyd on May 25 by a Minneapolis police officer who pressed his knee into his neck for eight minutes and 46 seconds.

BLM protesters across the country were met with force, often tear gassed or pepper sprayed. Biden said it laid bare an unequal justice system in the United States.

Many who took part in the chaos at the Capitol came from a "Save America Rally" held by Trump near the White House.

The protesters forced the House and the Senate to abruptly stop their counting of Electoral College votes. They climbed walls to the building, occupied the Senate chamber, ransacked congressional offices, and chased and fought with police officers.

At least five people died, including a woman shot dead by police, and a Capitol police officer who died later at a hospital. Police said they found two pipe bombs.

One demonstrator carried a Confederate flag, long associated with white supremacy, through the building. Photos showed a noose attached to a wooden beam.

About 68 people had been arrested by Sunday, 14 of whom face federal charges.

Stark difference

In contrast to those scenes seen by millions on live television, Biden said his granddaughter Finnegan sent him a photo from a BLM protest last year of National Guardsmen wearing camouflage lined up at the Lincoln Memorial. It exposed the stark difference in preparation for each event, he said.

Capitol police said they had been greatly outnumbered by Trump supporters. At least 50 Capitol and Washington police were injured.

Democratic Philadelphia Mayor Jim Kennedy called out the violence on Capitol Hill when compared with the treatment of BLM protesters.

"Could you imagine thousands of black people, people of color, invading the Capitol? What would have happened to them?" he told CNBC.

Former first lady Michelle Obama also waded into the debate on the role race played in the riot.

"Like all of you, I watched as a gang, organized, violent, and mad they had lost an election, laid siege to the United States Capitol," she wrote on Instagram.

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"There's one question I just can't shake. What if these rioters had looked like the folks who go to Ebenezer Baptist Church every Sunday? What would have been different? I think we all know the answer.

"This summer's Black Lives Matter protests were an overwhelmingly peaceful movement and yet in city after city, day after day, we saw peaceful protesters met with brute force."