This story has been updated as the official casualty toll rose.

About 235 people have been killed and more than 4,300 injured by two powerful earthquakes that struck northern Venezuela, the government said, as the toll continued to climb more than a day after the disaster and rescuers searched collapsed buildings for survivors.

What happened

The U.S. Geological Survey recorded a magnitude-7.2 quake followed about 40 seconds later by a stronger magnitude-7.5 tremor off the country's northern coast, NBC News reported. Both struck the densely populated northwest, and the shaking collapsed homes and other buildings in the capital, Caracas, and across the surrounding region. Numerous aftershocks followed.

Health Minister Carlos Alvarado said on Thursday evening that around 235 people had been confirmed killed and more than 4,300 injured, up from an earlier toll of 164, with officials warning the figure could rise further as rescuers reach more collapsed buildings and thousands remain unaccounted for, according to Al Jazeera. The government declared a nationwide state of emergency and deployed hundreds of first responders.

How high could it go

The USGS automated alert system — which estimates likely casualties from a quake's size, depth and the population exposed — has flagged a real risk of a far higher toll, putting a significant probability on deaths eventually running into the thousands or more. Those figures are probabilistic projections meant to guide the scale of the emergency response, not counts of the dead; the confirmed toll is what authorities have verified so far, and it is expected to climb as rescuers reach more collapsed buildings.

Damage and response

Simón Bolívar International Airport, the main gateway near Caracas, was closed because of structural damage, complicating the arrival of aid. Rescue teams worked through the night to reach people trapped in rubble.

The United States stepped up its response despite the turbulent recent relationship between the two governments. The US military said it was moving two warships — the amphibious ship USS Fort Lauderdale and the littoral combat ship USS Billings — closer to Venezuela, along with transport planes and helicopters, to support search-and-rescue and aid efforts, The Hill reported. President Donald Trump authorized a humanitarian package worth about $150 million, with funds directed to aid groups already working in Venezuela and to a UN-managed fund, according to CNBC. Neighboring countries also offered help. The coastal state of La Guaira was described by officials as among the hardest-hit areas, with some districts said to be largely devastated.

A seismically active region

Venezuela sits along the boundary between the Caribbean and South American tectonic plates, a zone with a long history of destructive earthquakes, including a catastrophic 1812 quake that devastated Caracas and a 1967 tremor that killed hundreds in the capital. Two strong quakes striking the same area within seconds compounds the danger, as structures weakened by the first shock are more vulnerable to the second.

This remains a developing story, and casualty and damage figures are expected to change as rescue and assessment efforts continue. newsparlor will update its reporting as verified information becomes available.