The death toll from Ecuador's earthquake has risen to 413 with more than 2000 injured, the country's government has said.
President Rafael Correa warned the death toll was likely to continue to rise, and said there were still people alive under the rubble of collapsed buildings.
He said it was a national tragedy, the biggest tragedy to hit Ecuador in the past seven decades.
Ecuador's most powerful recorded earthquake, measured at 7.8 magnitude, struck the country's Pacific coast on Saturday evening local time.
US Geological Survey said the earthquake struck at the shallow depth of 19.2 km. It was felt in Colombia and caused panic in Ecuador's inland capital Quito.
There have been about 230 aftershocks across the country.
A state of emergency has been declared and some 10,000 troops and 3500 police have been deployed in the affected areas.
In Pedernales, close to the epicentre, as many as 400 people are feared dead. Mayor Gabriel Alcivar said the "entire town" had been flattened.
"Pedernales is devastated. Buildings have fallen down, especially hotels where there are lots of tourists staying. There are lots of dead bodies," he told local media.
"We're trying to do the most we can but there's almost nothing we can do," he added, warning that looting had broken out.
More than 600 people have been treated for injuries at tents in the town's football stadium, with many others taken by ambulance or helicopter to regional hospitals.
In Portoviejo, a city of 300,000 people about 15km from the coast, rescuers rushed to search the debris of flattened buildings for survivors as residents reported the stench of decaying bodies beneath the rubble.
The vibrations also reduced part of the city's prison to rubble, allowing 100 inmates to escape. Some were recaptured but others remained on the run, Justice Minister Ledy Zuniga said on Twitter.
Teams from Switzerland, Spain and several Latin American countries have arrived to join the search effort.
Mr Correa visited some of the people affected by the disaster after cutting short a visit to Italy to return to his home country.
"I fear that figure will go up because we keep on removing rubble," the President said in a televised address.
"There are signs of life in the rubble, and that is being prioritised."
He warned the quake would cost Ecuador billions of dollars. It comes at a time when the oil-producing country is already reeling from the slump in global crude prices.
Correspondents said that while the country's energy industry survived the quake mostly intact - the main oil refinery of Esmeraldas was closed as a precaution - exports of bananas, flowers, cocoa beans and fish could be delayed because of impassable roads and hold-ups at ports.