The protest came just a day after Peru's prime minister, Gustavo Adrianzen, resigned to avoid a looming vote of no confidence in Congress.
His departure triggered the resignation of the entire Cabinet, although President Dina Boluarte swiftly reshuffled and reappointed most ministers to new posts.
Union leader Julio Campos dismissed the Cabinet reshuffle as ineffective, calling instead for real action against crime.
Peru is currently facing its highest levels of murder and extortion since 2017, according to official statistics.
