OTTAWA, Ontario — Prime Minister Harper of Canada apologized yesterday for a century of child abuse and assimilation policies at former government-run schools for aboriginals.

An estimated 150,000 children and youths were taken from their homes and forced to attend the schools, most of which closed in the 1970s. Survivors of the schools came from across Canada to attend the formal apology, and other parliamentary business was canceled.

“The treatment of children in Indian residential schools is a sad chapter in our history,” Mr. Harper said in a speech to Parliament in Ottawa. “Far too often, these institutions gave rise to abuse or neglect and there were inadequate controls, and we apologize for failing to protect you.”

The statement comes two years after the government and churches that helped run the schools settled the country’s largest-ever class-action lawsuit. The apology follows one by Prime Minister Rudd of Australia in February, to the “Stolen Generation” of Aborigines who were taken from their families and forced to blend into society.

Europeans who created settlements in Canada around the start of the 17th century pushed aboriginals out over time, moving from policies based on cooperation to dominance and assimilation, a 1996 government-sponsored panel report said. Children were taken from their parents and isolated in “Indian residential schools,” forbidden to speak their own languages and, in many cases, beaten or sexually abused.

Canada’s government says it had a role in the schools as early as 1874, a relationship that wound down in the 1970s. The last such school was shut in 1996. About 130 of the schools operated over that span.

As of April there were 90,000 applications for compensation stemming from the class-action settlement, according to the Department of Indian and Northern Affairs. The settlement allowed former students and their families to apply for a share of at least $1.86 billion that was awarded to victims.

Canada has about 1 million people who consider themselves part of the First Nations, a term used to describe aboriginals in the country, according to a 2006 census. Canada’s current total population is about 33 million.

“This is a historic event — finally Canada is standing up and taking responsibility,” the executive director of the 50,000-member National Residential School Survivors’ Society, Ted Quewezance, 55, said before the announcement. “There has to be substance and follow-up,” he said, including money to foster “healthy communities and healthy families.”

The memory of the schools still causes so much trauma for former students that the government’s Web site includes a telephone hotline for people who break down when reading about or watching the apology. Grief has been passed on to children of former students, with 26% having suicidal thoughts by age 12 compared with 18% for other aboriginal youths, according to the Ottawa-based Assembly of First Nations.

“Today is filled with incredibly strong emotions,” said Shawn Atleo, the regional chief of British Columbia Assembly of First Nations, who came to Ottawa yesterday with his father to help comfort survivors who attended the ceremony.

Mr. Atleo, 41, said his father was placed in a residential school where his tongue was pricked with a needle because he wouldn’t speak English. The apology “alludes to the promise of a better future,” he said.

Canada still has disputes with aboriginal peoples over unclean drinking water on reserves and land claims that remain unsettled after more than a century.