The first waves from a tsunami have reached Chile's coastline following a magnitude 7.6 earthquake, the country's navy says.
The tremor late on Wednesday was the strongest of several aftershocks that followed a 8.2-magnitude quake blamed for six deaths in the region on Tuesday.
The Pacific Tsunami Warning Center said the tsunami wave activity on the Chile coast on Thursday reached a height of 0.7 metres.
A tsunami warning put in place for Chile and Peru has now been cancelled.
The aftershock caused buildings to shake in the port of Iquique, which experienced some damage from the big quake on Tuesday. There were no immediate reports of new damage or injuries from the aftershock.
Al Jazeera's Lucia Newman, reporting from Iquique, said people were running to higher ground after the tsunami warning sounded in the town. She said power had been cut following the aftershock and fears were being pushed on radio that larger earthquakes were on their way.
"Thousands of people are sleeping outdoors at the moment, most of them with their children. They don't know if it will get stronger," Newman reported.
"Each time people's nerves get more thin. It's very frightening for them, especially people with families. It's quite a traumatising time here."
The latest tremor came 45 minutes after a strong 6.4-magnitude aftershock shook the same area.
The stronger aftershock's epicentre was 23km south of Iquique. The USGS said the aftershock had a depth of 20km.
Chile's President Michelle Bachelet, who was visiting the area to assess the damage after Tuesday's quake, was evacuated from her hotel in the northern city of Arica, according to local media reports.