WARNING: Distressing images.

Back-to-back earthquakes have rattled Venezuela, collapsing buildings in the capital, Caracas, and prompting residents to rush into the streets.

The United States Geological Survey said the quake measured 7.1 in magnitude, before a 7.5 magnitude quake. Its epicentre was located about 27 kilometres west of the coastal town of Morón, at a depth of roughly 13 kilometres.

“High casualties and extensive damage are probable and the disaster is likely widespread,” the USGS said, initially estimating the death toll would most likely range from 10,000 to 100,000.

Authorities did not immediately provide official estimates for deaths or injuries.

“We have buildings, homes and houses which have collapsed and we are taking care of things with everything we have available in terms of security, civil assistance,” Interior Minister Diosdado Cabello said on state television. “The fire department, police all have been activated.”

In Caracas, people evacuated homes and offices as the tremor shook the city.

The US Tsunami Warning System issued a tsunami threat for Puerto Rico and the US and British Virgin Islands following the quake, adding that islands off the coast of Venezuela - Aruba, Curacao and Bonaire - could also be hit by hazardous waves.

Interior Minister Diosdado Cabello said the initial quake could be felt in several states, adding the Altamira neighbourhood in Caracas had “alarming situations” with collapsed homes and buildings.

He urged people to remain outside as aftershocks could further damage some structures.

One wild video posted online was captioned: “Passengers panic and run for cover at Simón Bolívar International Airport in Maiquetía, Venezuela, as the terminal shakes and power flickers, resulting from a massive 7.5 magnitude earthquake off the coast of Caracas.”

Many Venezuelans were at home when the first quake hit, celebrating a public holiday commemorating an 1821 military victory which secured Venezuela’s independence from Spain.

Residents in Caracas rushed to evacuate as the quake shook buildings.

Maria Romero, an 80-year-old pensioner on the south side of Caracas, said that the police helped her evacuate her building.

“This earthquake was horrible, even worse than the one in 1967,” she added.

According to videos from Reuters witnesses, fire trucks were on the streets in Caracas, and the facades of some buildings had suffered significant damage.

Many residents in Caracas lost power or internet service right after the quake.

One witness said that cracks had formed up the side of their apartment and glass in the entry had shattered. Power went down shortly after, the witness added.

“Several walls in my building broke open or cracks formed,” a witness in Valencia, to the west of Caracas, told Reuters.

“As soon as it stopped (shaking) my husband and I evacuated.”

with AP and Reuters