Ecuador's strongest earthquake since 1979 has killed at least 77 people, causing severe damage and prompting the government to declare a state of emergency.
The 7.8-magnitude quake struck the northwestern part of the country at 7.58pm on Saturday (0958 AEST Sunday), the US Geological Survey said.
Its epicentre was 20km underground and about 170km northwest of the capital Quito.
Vice President Jorge Glas said the death toll had risen to 77 and at least 588 people were injured, according to CNN.
In an earlier televised address he had expressed fears of the toll rising as relief agencies were unable to reach the worst-hit areas.
A group of patients is evacuated from a clinic due to the presence of cracks in the building following a strong earthquake in Ecuador Source: AAP
There were some 50 aftershocks in the first four hours after the quake hit, the vice president said.
Glas, who is leading the country in the absence of President Rafael Correa, said the armed forces and national police were put on maximum alert.
Correa, who was at the Vatican for a conference, took to Twitter to express his "infinite love" for the families of the deceased, and called on his compatriots to show courage.
The president, who was rushing back from Italy and was expected to arrive in Ecuador by Sunday afternoon, said the damage was "serious" and called for citizens to remain "united".
In the country's largest city, Guayaquil, there were reports that a three-storey building had been levelled by the quake.
Some 16 people were reported dead in the city of Portoviejo, 10 in the coastal city of Manta and two in the province of Guayas, Glas said.
Some 71 houses had collapsed in the coastal city of Esmeraldas near the epicentre, according to El Telegrafo newspaper.
Electricity went down in parts of Quito, according to El Telegrafo.
The quake came as a result of movement at or near the plate boundary between the Nazca and Pacific plates, USGS said.
Ecuador - on the so-called Pacific "ring of fire" - has a history of such quakes. Since 1900, seven magnitude-7 or greater earthquakes have had an epicentre within 250km of the latest quake, the US agency said.
The Pacific Tsunami Warning Centre initially said tsunami waves reaching 0.3m to 1m above the tide level were possible for some areas along the Ecuadorian coast.
Tsunami waves of less than 0.3m above the tide level were possible along the coasts of Colombia, Costa Rica, Panama and Peru.
But by 0256 GMT the centre said that the "tsunami threat from this earthquake has now mostly passed".
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