SANTIAGO, Chile (AP) — Chile’s president is still struggling to bring calm to the streets one month into a potent protest movement that has dramatically altered the political landscape of the South American nation.

In televised comments late Sunday, President Sebastián Piñera acknowledged that excessive force has been used to clamp down on demonstrators with legitimate social demands and said abuses have been committed. He promised “no impunity” for anyone who commits acts of violence.

Twenty-six people have died in the protests. Thousands more have been injured in clashes with police who fire pellet guns directly at faces. At least 230 people have lost sight in an eye.

Demonstrators want reforms to education, health care and pensions. An agreement between political parties charts a course to potentially rewriting the constitution, another demand.