Chile’s government imposed a curfew on Tuesday and sent the army and national police officers to patrol the streets in response to a sweeping blackout that cut electricity to most of the country.

The massive outage, which began in the afternoon, affected eight million households in the South American nation of 19 million people, officials said. The affected area spanned 965 km, from Arica in the north — home to many of the country’s copper mines — to Los Lagos in the south, they said. In Santiago, it knocked out traffic lights, stranded people in elevators and shut down the subway network.

By midnight, power had been restored for 90 per cent of residential consumers, the National Electrical Coordinator said. Officials promised electricity would be restored to everyone by dawn.

The government had earlier announced a curfew from 10 pm to 6 am (local time) in the regions affected. Schools in those areas will be closed on Wednesday, with about 300,000 students affected, officials said. “Today has been a difficult day for millions of countrymen,” Gabriel Boric, the President, said at a news conference on Tuesday night.

As officials scrambled to restore power, nonfunctioning stoplights caused traffic chaos in Santiago and masses of commuters were evacuated from the subway, spilling out onto the streets and vying for spots on replacement buses.

“People were sprinting everywhere trying to get to the buses,” said Patricio Rodriguez, 35. “Everyone was desperate to get home.”

Rodriguez said he had to walk 14km to get to his aunt’s house. “People were driving the wrong way up the main roads, it was chaos,” he said. “It was like the Wild West — it felt lawless.”