(Adds approach to Congress in paragraph 2, protester quotes in paragraphs 4 and 19, Boluarte's meetings in paragraph 9)
LIMA, July 19 (Reuters) - Thousands of protesters took to the streets in Peru on Wednesday in marches organized by groups opposed to President Dina Boluarte's eight-month-old administration, while police took anti-riot measures against some demonstrators.
Groups of protesters in the capital Lima broke through a police line as they marched to Congress, but were dispersed when anti-riot police launched tear gas canisters at them.
Local television showed several thousand peaceful protesters affiliated with left-wing groups and unions marching in the sprawling city, while isolated incidents with police were reported in an Andean region where social conflicts have often flared.
"We want justice, peace and calm, and that Boluarte leaves immediately," demanded Lima protester Dionisio Flores.
Many Peruvians accuse Boluarte and her allies of illegitimately removing and jailing her leftist predecessor Pedro Castillo, which led to sometimes violent protests through last March that claimed 67 lives.
The unrest is also fueled by longstanding anger over rampant poverty and deep inequality that has persisted even as the major copper-producing nation has grown wealthier.
Peru, the second-largest supplier of the metal globally, could also face disruptions along its key mining corridor, where many communities support the protests and previously supported Castillo.
Some 24,000 police officers were deployed throughout the country in the lead up to the latest round of protests, according to officials.
Boluarte held closed-door meetings with her ministers on Wednesday, but she did not make any public comments.
Ground transport officials said protesters blocked at least eight highways by Wednesday afternoon, mostly in southern Arequipa and Cusco regions.
Police in riot gear watched over traffic on Lima's Panamericana highways, site of previous blockades.
Lima's main public transport agency announced it had temporarily suspended service on Wednesday as a preventative measure, though other transport firms in the area continued operating normally.
"We will respect the right of people to protest, but if these turn violent we will make rational use of force to impose authority," Lima police chief Roger Perez told reporters.
Jorge Pizarro, a spokesperson for one of the protest organizers, pledged that demonstrators "will not seek a confrontation with the police."
But in the Andean town of Huancavelica, protesters set the door of a government building ablaze. Police quickly doused it and then dispersed the crowd with tear gas, according to local television.
Aside from demanding Boluarte's removal, many protesters also want early elections, a new constitution and the right-wing Congress dissolved.
Boluarte, whose public approval has also plummeted, is under investigation for "genocide" and other violent acts committed during previous marches.
While her government has labeled the protests a threat to democracy, many protesters see Boluarte, Castillo's former vice president, as the bigger threat.
"This government is immoral, incompetent," said Martha Manami, who attended one of the marches. "It has used the armed forces to suppress us."
(Reporting by Marco Aquino; Writing by Sarah Morland; Editing by Alexander Villegas, Will Dunham, Josie Kao and Muralikumar Anantharaman)
