Brazilian security forces locked down the area around Congress, the presidential palace and the Supreme Court Monday, a day after supporters of ex-president Jair Bolsonaro stormed the seat of power in riots that triggered an international outcry. In stunning scenes reminiscent of the January 6, 2021 invasion of the US Capitol building by supporters of then-president Donald Trump, backers of Bolsonaro broke through police cordons and overran the seats of power in Brasilia, smashing windows and doors and ransacking offices. Initially overwhelmed security forces used tear gas, stun grenades and water cannon to fight back the rioters until they finally subdued them, reported AFP. Newly inaugurated President Luiz Inacio Lula da Silva, the veteran leftist who narrowly won Brazil's bitter, divisive October elections, condemned the invasions as a "fascist" attack. The far-right Bolsonaro meanwhile condemned "pillaging and invasions of public buildings" in a tweet. But the politician dubbed the "Tropical Trump" rejected Lula's claim he incited the attacks, and defended the right to "peaceful protests." Lula, who was in the southeastern city of Araraquara visiting a region hit by severe floods, signed a decree declaring a federal intervention in Brasilia, giving his government special powers over the local police force to restore law and order in the capital. "These fascist fanatics have done something never before seen in this country's history," said Lula, 77, who took office a week ago. "We will find out who these vandals are, and they will be brought down with the full force of the law." Lula returned to Brasilia and viewed the damage at the presidential palace and the Supreme Court. He said he would work out of the palace on Monday despite all the destruction. Police have made 170 arrests, media reports said. TV images showed police ushering Bolsonaro supporters in single file down the ramp from the Planalto presidential palace -- the same ramp Lula climbed a week earlier at his inauguration. The Senate security service said it had arrested 30 people in the chamber. - Brasilia security chief sacked - The chaos came after a sea of protesters dressed in military-style camouflage and the green and yellow of the flag flooded into Brasilia's Three Powers Square, invading the floor of Congress, trashing the Supreme Court building and climbing the ramp to the Planalto. Social media footage showed rioters breaking doors and windows to enter the Congress building, then streaming inside en masse, trashing lawmakers' offices and using the sloped speaker's dais on the Senate floor as a slide as they shouted insults directed at the absent lawmakers. Protesters damaged artworks, historic objects, furniture and decorations as they ran riot through the buildings, according to Brazilian media reports. One video showed a crowd outside pulling a policeman from his horse and beating him to the ground. Police, who had established a security cordon around the square, fired tear gas in a bid to disperse the rioters -- initially to no avail. A journalists' union said at least five reporters were attacked, including an AFP photographer who was beaten by protesters and had his equipment stolen. Hardline Bolsonaro supporters have been protesting outside army bases calling for a military intervention to stop Lula from taking power since his election win. Lula's government vowed to find and arrest those who planned and financed the attacks. Brasilia Governor Ibaneis Rocha fired the capital's public security chief, Anderson Torres, who previously served as Bolsonaro's justice minister. The attorney general's office said it had asked the Supreme Court to issue arrest warrants for Torres "and all other public officials responsible for acts and omissions" leading to the unrest. It also asked the high court to authorize the use of "all public security forces" to take back federal buildings and disperse anti-government protests nationwide. - 'Fraudulent election' - Protester Sarah Lima told AFP they were demanding a review of the "fraudulent election." Lula narrowly won the runoff by a score of 50.9 percent to 49.1 percent. Bolsonaro, who left for the US state of Florida on the second-to-last day of his term, has alleged he is the victim of a conspiracy against him by Brazil's courts and electoral authorities. "I'm here for history, for my daughters," said Lima, 27, wearing the yellow jersey of the Brazilian national football team -- a symbol Bolsonaro backers have claimed as their own -- and protesting with her young twin daughters. Fellow protester Rogerio Souza Marcos said the elections had been plagued by "multiple signs of fraud and corruption." Newly installed Justice and Public Security Minister Flavio Dino called the invasion "an absurd attempt to impose (the protesters') will by force." "It will not prevail," he wrote on Twitter. There was swift international condemnation of the protesters. The United Nations said it "vehemently condemns" the attacks. US President Joe Biden slammed the scenes as "outrageous," European Council President Charles Michel tweeted his "absolute condemnation," and French President Emmanuel Macron called for respect for Brazil's institutions and sent Lula "France's unwavering support." Even Italy's far-right Prime Minister Giorgia Meloni condemned the riots. A raft of Latin American leaders joined in, with Chilean President Gabriel Boric denouncing a "cowardly and vile attack on democracy" and Mexico's Andres Manuel Lopez Obrador calling it a "reprehensible coup attempt."