Update 12:34 p.m. EDT: At least five people are now dead after an earthquake struck off Chile's northern coast Tuesday evening, USA Today reported, citing Interior Minister Rodrigo Penailillo. The dead include four men and one woman, according to the report.

Update 11:43 p.m. EDT: Two people have been reported dead so far and several injured, according to a USA Today report, which cited the mayor of Tarapaca in northern Chile. The deaths were a result of heart attacks, the report said.

Update 11:10 p.m. EDT: Chile's interior minister says the armed forces have been called out after 300 prisoners escaped from a lockup in Iquique. Looting has been reported in the city. 

The tsunami warning will remain in force for at least six hours after the earthquake.

Update 10:30 p.m. EDT: The highest tsunami wave reported so far is 7.6 feet in Pisagua, Chile.

“Yes, that could do a lot of damage” in Chile, Paul Whitmore of the U.S. Tsunami Warning Center told the Los Angeles Times. “Once a tsunami gets going, a large-sized one, it will continue for hours, if not days. The danger will only decrease after the first six hours. They’re long-lasting events."

In California, waves are likely to be only about a foot higher than normal.

Update 9:55 p.m. EDT: The mayor of Arica in northern Chile, Salvador Urrutia, said his city has seen only minor injuries and no deaths from the earthquake, TV Chile reports. But power and phone service are out. The airport in Iquique is closed after damage to a control tower.

In the U.S., the director of the West Coast and Alaska Tsunami Warning Center said the greatest potential threat is to Hawaii, but analysts aren't yet issuing a watch or warning. The earliest waves would hit Hawaii is 3:24 a.m. local time, giving time to prepare.

Update 9:35 p.m. EDT: There is no serious damage to infrastructure or reports of victims, a Chilean government representative told Reuters.

"We have asked citizens to evacuate the entire coast ... there is no serious damage to houses ... there have been no people hurt," said Home Office Minister Mahmud Aleuy.

Update 9:25 p.m. EDT: Chilean authorities report at least four aftershocks. Landslides have blocked roads in the north.

The tsunami watch has been expanded as far north as El Salvador.

There have been numerous quakes in the same area over the past few weeks, but scientists said it was not clear whether they were a sign that a major quake was coming, the AP reports.

A magnitude-6.7 quake rattled the area on March 16, and more than 100,000 people were briefly evacuated from low-lying areas. No tsunami resulted from that quake, which caused little damage.

In 2010, a magnitude-8.8 quake and ensuing tsunami in central Chile killed more than 500 people, destroyed 220,000 homes and caused widespread damage to docks, riverfronts and seaside resorts.

Update 9:05 p.m. EDT: The earthquake magnitude has been upgraded to 8.2 by the USGS. A Chilean agency said it was 8.3. 

The Chilean navy reports tsunami waves hitting northern regions. Buildings in Bolivia and Peru shook, NPR reported.

Update 8:50 p.m. EDT: The Pacific Tsunami Warning Center reports tsunami waves in northern Chile and southern Peru. A 6.9- foot wave was seen at Iquique.  

Original story:

A major earthquake, estimated at magnitude 8.0, struck in the Pacific Ocean, 99 kilometers (about 62 miles) northwest of Iquique, Chile, Tuesday evening, the U.S. Geological Survey said.

The quake occurred at 23:46 UTC (7:46 EST) at a depth of 6.2 miles under the ocean floor.

A tsunami warning is in effect for Chile Peru and Ecuador, and a tsunami watch for Colombia, Panama and Costa Rica, the National Weather Service said.

The tsunami threat to Hawaii still was being evaluated. The U.S. National Tsunami Warning Center was working to determine the level of danger for Alaska, Washington, Oregon and California, as well as Canada's British Columbia.

“Sea level readings indicate a tsunami was generated,” the agency said.

The Chilean government has urged residents of northern regions to evacuate the coastline.

This is a developing story. Check here for updates.