Five people died after looters torched a garment factory near Chile's capital Santiago, bringing the death toll in violent protests to at least seven.
The military and police used tear gas and water cannon against protesters and a curfew were imposed in major cities.
A state of emergency already in place in Santiago is to be extended to cities in the country's north and south.
The unrest, sparked by a now-suspended metro fare hike, has widened to reflect anger over living costs and inequality.
In a late-night statement on television on Sunday, President Sebastián Piñera said: "We're at war against a powerful enemy, who is willing to use violence without any limits."
There is set to be major disruption on Monday with many banks, schools and shops expected to remain closed.
SOURCE: BBC