The destruction of the building, a near-century-old mansion in the city centre, was described by officials as the loss of a “monumental asset”. Authorities are investigating the causes.
Romero claimed the blaze was “duly planned and arranged”.
Thousands of protesters descended on Lima this week calling for change and angered by the protests’ mounting death toll, which officially stood at 45 on Friday.
The unrest had until this week been concentrated in Peru’s south.
In the Cusco region, Glencore’s major Antapaccay copper mine suspended operations on Friday after protesters attacked the premises – one of the largest in the country – for the third time this month. Swiss-based Glencore is Australia’s largest coal miner.
Airports in Arequipa, the southern city of Juliaca and Cusco – gateway to Machu Picchu – were also attacked by demonstrators, delivering a fresh blow to Peru’s tourism industry. Australians were among hundreds of tourists stranded as the protests erupted near the popular Incan ruins.
“It’s nationwide chaos, you can’t live like this. We are in a terrible uncertainty – the economy, vandalism,” said Lima resident Leonardo Rojas.
The government has extended a state of emergency to six regions, curtailing some civil rights.
But Boluarte has dismissed calls for her to resign and hold snap elections, instead calling for dialogue and promising to punish those involved in the unrest.
“All the rigour of the law will fall on those people who have acted with vandalism,” Boluarte said.
Some locals pointed the finger at Boluarte, accusing her of not acting to quell the protests. Some say Castillo is their rightful president.
Human rights groups have accused the police and army of using deadly firearms. The police say protesters have used weapons and homemade explosives.