New Delhi: Prime Minister Narendra Modi on Monday expressed his deep concern over rioting and vandalism against state institutions in Brasilia, extending his full support to the Brazilian authorities.

"Deeply concerned about the news of rioting and vandalism against the State institutions in Brasilia. Democratic traditions must be respected by everyone. We extend our full support to the Brazilian authorities," tweeted PM Modi.

US President Joe Biden condemned the 'assault on democracy' in Brazil.

Biden tweeted, "I condemn the assault on democracy and on the peaceful transfer of power in Brazil. Brazil's democratic institutions have our full support and the will of the Brazilian people must not be undermined. I look forward to continuing to work with @LulaOficial."

United Nations Secretary-General Antonio Guterres condemned the 'assault on Brazil's democratic institutions'. He emphasised that the will of the Brazilian people and democratic institutions must be respected.

"I condemn the assault on Brazil's democratic institutions that took place today. The will of the Brazilian people and democratic institutions must be respected. I have full confidence that it will. Brazil is a great democratic country," Guterres tweeted.

Supporters of former Brazilian President Jair Bolsonaro broke into the country's congressional building, Supreme Court and presidential palace on Sunday.

The breaches come about a week after the inauguration of President Luiz Inacio Lula da Silva, who defeated Bolsonaro in a runoff election on October 30.

Videos on social media showed Bolsonaro supporters smashing windows and furniture in the National Congress and Supreme Court buildings on Sunday, reported Al Jazeera.

They climbed onto the roof of the Congress building, where Brazil's Senate and Chamber of Deputies conduct their legislative business, unfurling a banner that read "intervention" and an apparent appeal to Brazil's military.

Images on TV channel Globo News also showed protesters roaming the presidential palace, many of them wearing green and yellow - the colours of the Brazilian flag, which have also come to symbolize the Bolsonaro government.

Security forces used tear gas in an effort to push back the demonstrators with local media estimating about 3,000 people were involved in the incident, reported Al Jazeera.

The siege, which lasted a little over three hours, comes just a week after the inauguration of Bolsonaro's leftist rival, President Luiz Inacio Lula da Silva.

Around 3,000 supporters of Brazil's far-right ex-president Jair Bolsonaro break into Brazil Congress building, presidential palace in a dramatic protest against President Silva's inauguration last week, who defeated Bolsonaro in a runoff election on October 30.

Bolsonaro challenged the election results and has not explicitly conceded, though he said he would cooperate with the transition of power.

Meanwhile, police have since cleared the massive crowds from government buildings and made at least 400 arrests, according to CNN Brasil and a local official.

At least 400 people have been arrested after pro-Bolsonaro supporters stormed key government buildings in Brazil's capital, said Ibaneis Rocha, the governor of the country's Federal District.

The three main government buildings -- the Supreme Court, the presidential palace and the congressional building -- involved in today's breach have been cleared of protesters, police said Sunday, according to CNN Brasil.

Moreover, Justice Minister Flavio Dino said that Brazil's government will adopt more measures aimed at strengthening the capital of Brasilia.

Dino told reporters "there are still people on the internet saying that they are going to continue with terrorist acts. And they will not be able to destroy Brazilian democracy. They won't."

He also described Sunday's events in Brasilia as 'a coup', reported CNN.

In the latest development, Facebook's parent company Meta declared the unrest in Brazil a 'violating event' on Sunday, adding it would "remove content that supports or praises" protesters who breached government buildings, reported CNN.

"In advance of the election, we designated Brazil as a temporary high-risk location and have been removing content calling for people to take up arms or forcibly invade Congress, the Presidential palace and other federal buildings," Meta spokesperson Andy Stone told CNN.

"We're also designating this as a violating event, which means we will remove content that supports or praises these actions. We're actively monitoring the situation and will continue removing content that violates our policies."