The Chilean navy has admitted that some deaths in the tsunami triggered by the earthquake four days ago could have been avoided.

Admiral Edmundo Gonzalez said some lives could have been spared in coastal areas if a tsunami warning had been issued earlier.

"We weren't clear in the information which we communicated because we were not precise enough to be able to tell the president whether to maintain or cancel [the
tsunami warning]", Gonzalez said on Wednesday.

Chilean emergency officials and the military have been blaming each other for not clearly warning coastal villages of tsunami after the 8.8 magnitude quake.

'People upset'

Al Jazeera's Lucia Newman, reporting from the city of Concepcion, said some resident's in coastal areas had received tsunami warnings.

"I visited one seaside village where people did get a warning. Police went around with loudspeakers telling people to leave ... But in other places they never received that warning. It was very uneven," she said

"All in all people are upset, they're angry. They're blaming their local authorities and they're also blaming the central government for the way this whole thing has been handled."

The quake that struck 92km northeast of Concepcion at a depth of 63km on Saturday has claimed at least 795 lives, destroyed half-a-million homes and made up to two million people homeless across a large swathe of the country.

A strong aftershock caused panic in Conepcion on Wednesday but no injuries or damage were reported.

Tremors were also felt in the capital, Santiago.

Rescue workers have stepped up their search for survivors in the quake-hit south-central parts of the country. 

Search teams with sniffer dogs were scouring cities and villages while bodies were pulled out of mountains of rubble.

The death toll was likely to rise sharply as relief teams reached more isolated areas, including fishing villages and resorts wrecked by giant sea waves. 

Some reports were putting the number of missing as high as 500 in the city of Constitucion alone.

Looting quelled

Meanwhile, police and troops have managed to quell the looting and violence that erupted in Concepcion in the immediate aftermath of the disaster.

No looting was reported overnight with about 7,000 soldiers patrolling the streets to keep order.

Authorities had deployed additional troops after survivors, angry over inadequate aid, broke into shops and ransacked shelves for food.

The government of Michelle Bachelet, the president, has been criticised for its handling of the crisis.

Bachelet has acknowledged that rescue efforts have been slow, in part because of mangled roads, downed bridges and power cuts. But officials also misjudged the extent of the damage, initially declining offers for international aid.

Bachelet has later asked donors for desalination plants and power generators. The US and other governments have pledged to send aid.

Canada has committed up to $2m to help quake victims and Cuba has said it would send a 27-person medical team.

Some analysts estimate the damage could cost Chile up to $30bn, or about 15 per cent of its gross domestic product.