The first 7.2-magnitude quake was followed seconds later by an even stronger 7.5-magnitude one, according to the US Geological Survey (USGS), with both occurring close to the surface, making destruction more severe.
Many more people are feared dead, with others left homeless or too afraid to stay in damaged, unsafe buildings sleeping in the streets after the disaster.
The earthquakes struck at 18:04 local time (22:04 GMT) on Wednesday - a national holiday in Venezuela, meaning more people would have been at home than on a normal weekday.
Both quakes were shallow - the first centred 20.3km below the surface and the second at a depth of 10km, according to USGS.
Jorge Rodríguez, the president of Venezuela's National Assembly, reported on Thursday that the death toll had risen, after the country's interim President Delcy Rodríguez declared a state of emergency.
Several countries have pledged to help the rescue efforts, with the US promising $150m (£113m) in aid.
