The protests took place Thursday, Canada's national day, when cities throughout the country normally hold celebrations to mark the country's colonization by the British in 1867. Many of those celebrations were more subdued or canceled this year in response to the discovery of the unmarked graves, CNN reported.
Protesters cheered as they brought down a statue of Queen Victoria and a smaller, nearby, statue of Queen Elizabeth II near the legislative building in Winnipeg, Manitoba. Queen Victoria was monarch of Britain when Canada was colonized.
"We obviously condemn any defacing of statues of the queen," the British government said in reaction.
"Our thoughts are with Canada's Indigenous community following these tragic discoveries and we follow these issues closely and continue to engage with the government of Canada with indigenous matters."
The BBC reported that police used a stun gun during its arrest of one man at the scene. Crowds chanted "no pride in genocide" during the protest.
The Canadian government forcibly removed more than 150,000 Indigenous children from their families during the 19th and 20th centuries, relocating them to schools where they were forced to assimilate. The schools have faced criticism, not only for removing children from their families, but also for housing them in unsanitary and poorly heated conditions.