Venezuela’s acting president, Delcy Rodríguez, declared a state of emergency Wednesday evening after two powerful earthquakes struck the country less than a minute apart, collapsing buildings in the capital, Caracas, and killing at least 164 people, Rodríguez said. At least 971 others were injured, according to the interim leader.

The U.S. Geological Survey recorded a magnitude-7.2 earthquake followed less than a minute later by a magnitude-7.5 “mainshock.” The USGS warned that “high casualties and extensive damage are probable and the disaster is likely widespread.” The quakes were among the largest in Venezuela’s history and were felt across much of the country.

The worst destruction appeared concentrated in and around Caracas, a densely populated city struck on a national holiday when more residents than usual would have been at home. Videos on social media showed panicked passengers racing through the corridors of the nearby Simón Bolívar International Airport seeking cover from falling debris. Rodríguez said the airport had been closed after sustaining “severe damage” and that the metro and train systems had been halted.

A Guardian reporter on the ground saw at least three buildings that had collapsed in Altamira, an upmarket area of Caracas that houses many foreign embassies. The quakes struck shortly after 6 p.m. local time Wednesday.

Experts have said the death toll could rise further as rescue workers continue to search through collapsed structures.