At least five people were killed and 1 million evacuated from affected areas, when a powerful 8.3-magnitude earthquake struck Chile Wednesday, the director of the National Office of Emergency for the Chilean Ministry of Interior, Ricardo Toro, announced at a Santiago news conference early Thursday morning.

[Breaking news alert, posted at 10:53 p.m. ET Wednesday]

At least three people were killed when a powerful earthquake struck Chile on Wednesday, President Michelle Bachelet said. The victims included a 35-year-old woman who was killed by a falling roof, a 20-year-old woman who was killed by falling rocks and a man in his 80s who had a heart attack, Bachelet said.

[Previous story, posted at 10:24 p.m. ET Wednesday]

A powerful 8.3-magnitude earthquake struck off Chile's coast on Wednesday, triggering a tsunami alert and coastal evacuations.

A woman was killed in the city of Illapel, Chilean National Police spokesman Oscar Llanten told CNN sister network CNN Chile . At least seven people were injured in the quake, he said, three of whom are in serious condition.

There were also reports of damages to homes in Illapel, Interior Minister Jorge Burgos told reporters.

According to a preliminary assessment from the U.S. Geological Survey , the quake's epicenter was about 54 kilometers (34 miles) west of Illapel. It occurred around 7:54 p.m. (6:54 p.m. ET) and had a depth of 33 kilometers (20.5 miles), USGS said.

Chile's national emergency agency issued a tsunami alert, ordering evacuations in coastal areas from Arica to Puerto Aysen.

Flooding, power loss

Large tsunami waves have been observed along the Chilean coast, near the quake's epicenter. In Coquimbo, Chile, a wave was measured at more than 15 feet, according to the U.S. National Tsunami Warning center.

Pictures taken inside a shopping mall in La Serena, in the coastal city just north of Coquimbo, showed walls and signs toppled to the floor, ceiling tiles caved in as well as chairs, benches and tables covered in rubble.

Coquimbo Mayor Cristian Galleguillos told CNN Chile the city was starting to see flooding and 95% of the city had lost electrical power. Residents had evacuated before waves started hitting the coastline, he said.

At least 12 aftershocks of magnitude 4.9 or higher rattled residents in the area around the first quake's epicenter within less than two hours, according to USGS.

A series of aftershocks could be felt in the country's capital, about 230 kilometers (145 miles) away from the quake's epicenter, CNN Chile reported.

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"Everybody ran outside. The windows rattled. Things fell. ... The impact was strong," said Emily Hersh, who lives in Santiago. "Even after I stepped outside, I felt the ground moving."

Fabrizio Guzman, emergency communications manager in Chile for World Vision, said the the earthquake hit during rush hour, causing traffic snarls that left many people stuck in the streets as they tried to get home.

"There were many people afraid, running in the streets, when the shaking started," he said in a written statement. "The earthquake felt really intense and seemed to last for several minutes."

Tsunami watch

"Widespread hazardous tsunami waves are possible" along the coast of Chile and Peru, the Pacific Tsunami Warning Center said , and a tsunami watch is in effect for Hawaii.

A tsunami watch is issued "to alert emergency management officials and the public of an event which may later impact the watch area," the center says. A warning is issued when a "potential tsunami with significant widespread inundation is imminent or expected."

Even New Zealand, which is some 6,000 miles away from the quake's epicenter, is on guard for possible tsunami waves.

The country has issued a tsunami warning. Shane Bayley of New Zealand's Ministry of Civil Defence and Emergency Management told CNN strong tidal currents and large waves are expected in some areas.

'Ring of Fire'

Chile is in one of the most earthquake-prone regions in the world.

The country sits on an arc of volcanoes and fault lines circling the Pacific Ocean known as the "Ring of Fire." The area experiences frequent earthquakes and volcanic eruptions.

Since 1973, Chile has had more than a dozen quakes of magnitude-7.0 and above.