Northern Chile has been rattled by powerful aftershocks a day after an earthquake struck the region, leaving 15,000 people homeless.
Thursday's two tremors were measured at 6.2 and 6.8 magnitude by the US Geological Survey.
They came as Chilean President Michelle Bachelet visited the disaster zone following Wednesday's quake, which killed two people and injured some 150.
The major 7.7 magnitude quake wrecked 4,000 homes and other infrastructure.
Tents have been set up to help residents who were forced to sleep outdoors under cold desert skies.
On Wednesday in Tocopilla city two women, aged 88 and 54, were crushed to death by collapsing walls.
Lasting about 50 seconds, the earthquake was felt thousands of kilometres away in Sao Paulo, Brazil.
Electricity, water and phone lines were cut in some areas by the quake, which struck around midday on Wednesday 1,260km (780 miles) north of the capital, Santiago.
Thursday's aftershocks occurred nearby only 35km (21.7 miles) deep, 93km (58 miles) north-east of mining capital Antofagasta.
They came as President Bachelet and four cabinet ministers visited Antofagasta and other affected areas.
Interior minister Belisario Velasco has formally declared the region a catastrophe zone, a measure which helps speeds up the delivery of aid.
Tocopilla Mayor Luis Moncayo said that at least 4,000 people in the port city had been left homeless by Wednesday's quake and some 1,200 buildings demolished.
About 500 emergency housing units have been sent to the city of 27,000 people.
The local hospital was also damaged and patients were being treated at a portable military hospital, officials said.
Paula Saez, a worker with aid body World Vision International, told Reuters news agency from Tocopilla: "People here are pretty afraid.
"There have been so many aftershocks that start with a big noise, a humming noise, and then the ground starts moving and people start to run away."
In Maria Elena on Wednesday, a small town south-east of Tocopilla, 20 people were hurt and 70% of the town's houses were destroyed.
In Antofagasta, the airport was damaged, Chilean radio reported, while some 45 people were injured.
Chile's largest copper mines are in the quake zone, and production was temporarily halted on Wednesday. The nation is the world's largest copper producer.
In August more than 500 people died when an 8.0 magnitude quake struck neighbouring Peru just south of the capital, Lima.
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