Luiz Inácio Lula da Silva, the president of Brazil, has pledged to punish Jair Bolsonaro's supporters for storming Congress.
In addition, followers of the deposed far-right leader surrounded the White House and invaded the Supreme Court.
However, after hours of fighting, police took back control of the structures in the nation's capital, Brasilia, on Sunday night.
Lula visited the Supreme Court building after arriving in the city to observe the damage firsthand.
According to Flavio Dino, minister of justice, 200 persons have already been detained.
The Supreme Court has suspended Ibaneis Rocha, the governor of Brasilia, from office for 90 days. In addition to failing to stop the brawl, Justice Alexandre de Moraes charged him with remaining "painfully mute" in the face of the assault.
Leftist politicians and organisations are calling for pro-democracy demonstrations all around Brazil.
Just a week after Lula's inauguration, hundreds of protesters wearing yellow Brazil football shirts and flags overran police and ransacked the centre of the Brazilian state.
Before sending the national guard into the city to restore order, the seasoned left-wing leader was obliged to proclaim an emergency.
He also mandated the 24-hour shutdown of the capital's core, which includes the major boulevard where the government buildings are located.
The invasion, according to Mr. Dino, was a "absurd attempt to impose [the protestors'] will by force," as he claimed that over 40 buses that had been used to carry protesters to the capital had been taken.
Bolsonaro last week departed the country rather than participate in the inauguration rituals, when he would have handed over the recognisable presidential sash. Mr. Bolsonaro has frequently refused to recognise that he lost the election in October.
Six hours after the unrest started, the 67-year-old, who is thought to be in Florida, condemned the assault and denied being responsible for motivating the rioters in a post on Twitter.
Before he arrived in Brasilia, Lula stated that the events there had "no precedent in the history of our country" and referred to the violence as "acts of vandals and fascists."
He also targeted security personnel, charging them with "incompetence, bad faith, or malice" for failing to prevent protesters from entering Congress.
He remarked, "You'll see in the pictures that they're [police officers] leading people on the walk to Praca dos Tres Powers. They will all be made to pay with the might of the law once we identify the financiers of these vandals who travelled to Brasilia.
O Globo, a Brazilian news agency, released a video of some police grinning and posing for pictures while protesters occupied the congressional campus in the backdrop.
Joe Biden, the US president, tweeted: "I deplore Brazil's attempt to undermine democracy and a transition of power through peaceful means. We fully support Brazil's democratic institutions, and the will of the Brazilian people must not be disregarded."
While some demonstrators broke windows, others entered the Senate chamber and jumped on chairs and used benches as slides.
Social media videos depict demonstrators yanking a policeman from his horse and assaulting him outside the structure.
National TV footage depicts police holding scores of demonstrators wearing yellow vests outside the presidential palace.
Other suspects are seen being brought out of the building with their hands bound behind their backs.
On the lawns in front of the parliament and along the kilometer-long Esplanada road, which is lined with government buildings and historical sites, protesters had gathered since early in the day.
With the roads closed for nearly a block surrounding the parliament area and armed police pairs manning each entry, security had appeared to be tight.
On Sunday morning local time, the BBC reported that there were roughly 50 police officers there. Cars were being turned away at entry points, while people coming in on foot were being frisked and their baggage checked.
When approached by reporters, demonstrators defended their acts without hesitation.
Lima, a 27-year-old production engineer, declared: "After this rigged election, we need to re-establish order."
For my daughters, history is why I'm here, she told the AFP news agency.
Others in the capital city condemned the violence and said it was a sad day for the nation.
Daniel Lacerda, 21, told the BBC, "I voted for Bolsanaro, but I don't agree with what they're doing. If you disagree with the president, just say so and move on; don't hold demonstrations or engage in acts of violence like they are.
And many are making analogies to the takeover of the US Capitol on January 6, 2021 by supporters of Mr. Bolsonaro's ally, Donald Trump.
Supporters of Bolsonaro set up camps in places all around Brazil, some of them in front of military facilities. This is due to the fact that his most fervent fans want the military to step in and rig the elections they claim were fraudulent.
The camps in Brasilia had been taken down, and there had been no unrest on the day Lula was sworn in, so it appeared that his election had slowed their movement.
However, Sunday's events demonstrate how hasty those projections were.
Latin American leaders have denounced the violence:
Brazil has the "full support" of Chile, according to Chilean President Gabriel Boric, "in the face of this cruel and terrible attack on democracy."
Gustavo Petro, the president of Colombia, declared that "fascist [had] chosen to organise a coup."
Mexico offered "complete support for President Lula's administration, elected by popular will," according to Mexican Foreign Minister Marcelo Ebrard.
Additionally, French President Emmanuel Macron promised Lula his country's "unwavering support" and stated that Lula's "desire of the Brazilian people and the democratic institutions must be honoured."
