The United States on Thursday marked one year from the deadly attack on the Capitol by a mob seeking to overturn the outcome of the 2020 presidential election, with the nation still struggling to revive its standing as a beacon of democracy.

President Joe Biden called for unity and further efforts to defend democracy, while slamming his Republican predecessor Donald Trump for becoming the first U.S. leader to respond to an election loss by attempting to thwart the peaceful transfer of power. Biden placed responsibility on Trump for inciting his supporters toward an "armed insurrection."

Amid the deep political divisions in the country, however, unity has been an elusive goal as many Republicans refuse even to accept Biden as a legitimate president.

U.S. President Joe Biden delivers remarks in Statuary Hall of the U.S. Capitol in Washington on Jan. 6, 2022, marking the one-year anniversary of the attack seeking to overturn the 2020 presidential election results. (Getty/Kyodo)

"Are we going to be a nation that accepts political violence as a norm? Are we going to be a nation where we allow partisan election officials to overturn the legally expressed will of the people?" the Democratic president said as he addressed the nation at the Capitol.

"We cannot allow ourselves to be that kind of nation," Biden said.

In a fiery 20-minute speech on the first anniversary, he stepped up his accusations against Trump, pointing out the then president's initial inaction as the mob, including right-wing extremists, swarmed the Capitol while Congress was engaged in a process to certify Biden's election win.

"Here's the truth. The former president of the United States of America has created and spread a web of lies about the 2020 election," Biden said. "He's done so...because his bruised ego matters more to him than our democracy or our Constitution."

Five people died in the incident, including a police officer and a Trump loyalist who was shot by police inside the Capitol. Congress members sought secure locations as intruders violently clashed with police, smashed windows and ransacked offices.

Trump, who maintains a tight grip on his party and is hinting about running in the next presidential election in 2024, doubled down on his assertion that the 2020 election was "rigged" against him and hit back at Biden.

"This political theater is all just a distraction for the fact Biden has completely and totally failed," Trump said, claiming the incumbent is "destroying" the country with "insane policies" on matters such as the coronavirus pandemic and immigration.

"Never forget the crime of the 2020 Presidential Election. Never give up!" he said in another statement.

The Biden administration has been pushing to combat misinformation and promote human rights as part of efforts to strengthen the country's democratic foundations, but it has also voiced concerns over an increase in what is viewed as voter-suppression laws at the state level.

The country's views on the Jan. 6 incident remain divided, with one poll released by the University of Massachusetts-Amherst in December showing 71 percent of Republicans -- and one-third of the nation -- continuing to believe Biden's victory was illegitimate.

The incident is also seen to have had an impact globally, at a time when the Biden administration seeks to rally other democracies to push back against autocracies such as China and Russia seeking to increase their influence.

"From China to Russia and beyond, they're betting that democracy's days are numbered. They've actually told me democracy is too slow, too bogged down by division to succeed in today's rapidly changing, complicated world," Biden said.

"They're betting America will become more like them and less like us," he said. "I do not believe that. That is not who we are."

Frank Sesno, a political analyst, said the Capitol siege has shown America is "less of a beacon than we commonly thought" and such recognition affects its standing around the world "because so much of America's standing was on the values it was built upon and the perceived stability of and for those values."

American democracy will now be measured through "several important moments" over the next two years, including the process of holding accountable those involved in the Capitol attack as well as the next presidential election, said Sesno, who serves as the director of strategic initiatives at the George Washington University School of Media and Public Affairs.

More than 700 people so far have been arrested and charged across the country for their roles in the attack.

An investigation committee set up in the Democratic-controlled House of Representatives is looking into Trump's responsibility in the incident. An interim report may come out by summer and a final report before the November midterm elections.

(Andrew Nicholas contributed to this story.)