Thousands of protesters in Peru, many from the country’s heavily indigenous south, descended on Lima, the capital, on Thursday, angered by a mounting death toll since unrest erupted last month and calling for sweeping change.

Police estimated the march at around 3,500 people, but others speculated it attracted more than double that.

Rows of police in riot gear faced off against rock-hurling protesters on some streets, and one historic building in the city’s historic center caught fire late on Thursday.

The building, on San Martin Plaza, was empty when the massive blaze ignited from unknown causes, a firefighter commander told local radio.

Canada-based miner Hudbay said in a statement that protesters had entered the site of its Peru unit, damaging and burning key machinery and vehicles.

“This has not been a protest; this has been a sabotage of the rule of law,” Prime Minister Alberto Otarola said Thursday evening alongside President Dina Boluarte and other government ministers.

Interior Minister Vicente Romero disputed claims circulating on social media that the Lima blaze had been caused by a police officer’s tear gas grenade.

Over the past month, raucous and sometimes deadly protests have led to the worst violence Peru has seen in more than two decades, as many in poorer, rural regions vent anger at the Lima establishment over inequality and rising prices, testing the copper-rich Andean nation’s democratic institutions.

Protesters are demanding the resignation of Boluarte, snap elections and a new constitution to replace the market-friendly one dating back to the days of right-wing strongman Alberto Fujimori in the 1990s.

“We want the usurper Dina Boluarte to step down and call for new elections,” said protester Jose De la Rosa, predicting the street protests would only continue.

The protests have been sparked by the dramatic Dec. 7 ouster of leftist former President Pedro Castillo after he tried to illegally shutter Congress and consolidate power.

In buses and on foot, thousands journeyed to Lima on Thursday, carrying flags and banners blasting the government and police for deadly clashes in the southern cities of Ayacucho and Juliaca.

The unrest spread far beyond the capital.

In southern Arequipa, police fired tear gas at hundreds of protesters who tried to take over the airport, local television showed, leading officials to announce the suspension of operations at the Arequipa and Cusco airports.

Boluarte said on Thursday evening that the airports, as well as one in the southern city of Juliaca, had been attacked “in a concerted manner.”

“All the rigor of the law will fall on those people who have acted with vandalism,” Boluarte said.

The mounting death toll stands at 45, according to the government ombudsman, with the latest victim on Thursday coming from southern Puno region, a woman who succumbed to injuries from a day earlier. Another nine deaths are attributed to accidents related to protest blockades.