SANTIAGO, Chile -- Soldiers and extra security forces were on hand in parts of northern Chile Wednesday to prevent looting and to round up hundreds of inmates who escaped after a magnitude-8.2 earthquake struck the region, leaving at least six people dead.
The victims died of either heart attacks or being crushed to death, Interior Minister Rodrigo Penailillo said.
The quake struck at 8:46 p.m. local time and was centered in the Pacific Ocean 950 miles from the capital, Santiago, the United States Geological Survey reported.
Tsunami warnings, which forced 900,000 people to flee northern coastal areas, were issued during the night but were lifted before morning, the newspaper Nacional reported.
Six-foot high waves hit cities along the northern coast, but did not cause any damage or disruption, the Associated Press reported.
Hardest hit by he quake was the northern port city of Iquique, where more than 300 prisoners escaped from a women's jail. Power outages and flooding were also reported in the city of more than 180,000 residents.
Residents who fled their low-lying homes after the tsunami warning sent to the local soccer stadium, the Los Angeles Times reports.
At least two fires that erupted in the city were contained during the night, the Financial Daily Online reports.
President Michelle Bachelet declared a state of emergency in the region and sent a military plane with 100 anti-riot police to join 300 soldiers deployed to prevent looting and help round up prisoners.
"The country has done a good job of confronting the emergency. I call on everyone to stay calm and follow the authorities' instructions," Bachelet tweeted.
Chile is one of the world's most earthquake-prone countries because just off the coast, the Nazca tectonic plate plunges beneath the South American plate, pushing the towering Andes cordillera to ever-higher altitudes.
The latest activity began with a strong magnitude-6.7 quake on March 16 that caused more than 100,000 people to briefly evacuate low-lying areas.
Hundreds of smaller quakes followed in the weeks since, keeping people on edge as scientists said there was no way to tell if the unusual string of tremors was a harbinger of an impending disaster.
Contributing: Associated Press