The latest earthquake hit 70 km (44 miles) off the Pacific coast town Esmeraldas at a depth of 10 km, the Pacific Tsunami Warning Center said. That was not far from the epicenter of Saturday's 7.8 magnitude quake. .
Witnesses in the zone said two strong tremors of about 30 seconds each were felt in the early hours in Cojimies, down the coast from the weekend earthquake. People woke up and rushed into the street.
No tsunami warning was issued. The quake was not felt in the highland capital of Quito, and there were no immediate reports of major damage.
Ecuador's Geophysical Institute said a 6.2 magnitude earthquake at 3.33 local time (0833 GMT) was followed by a series of aftershocks. The US Geological Survey (USGS) put the magnitude at 6.1.
Saturday's quake killed 480 people, left another 107 missing, and injured more than 4,600. About 1,500 buildings were destroyed, mudslides were triggered and roads torn up. Some 20,500 people were left sleeping in shelters.
Supervising rescue work in the disaster zone, President Rafael Correa said the weekend quake inflicted $2 billion to $3 billion of damage to the oil-dependent economy and could knock 2 to 3 percentage points off growth.
Lower crude revenues had already left Ecuador, a poor Andean nation of 16 million people, facing near-zero growth, cutting investment and seeking financing.
In isolated villages and towns, survivors struggled without water, power or transport, although aid was trickling in. Up and down Ecuador's Pacific coast, sports stadiums served as both morgues and aid-distribution centers.
Scores of foreign aid workers and experts have come to help. About 14,000 security force members are keeping order, but sporadic looting has been reported.
Rescuers were losing hope of finding more people alive, although relatives of the missing begged them to keep looking."There is still a small margin of time to find survivors," Correa said. "But I don't want to give excessive hope."
The latest earthquake hit 70 km (44 miles) off the Pacific coast town Esmeraldas at a depth of 10 km, the Pacific Tsunami Warning Center said. That was not far from the epicenter of Saturday's 7.8 magnitude quake.