Two powerful earthquakes have struck Venezuela, bringing down buildings in Caracas, trapping people under rubble and prompting the government to declare a state of emergency as rescue teams searched for survivors.The first quake, with a magnitude of 7.2, struck about 160 km west of the capital. It was followed less than a minute later by a stronger 7.5-magnitude tremor, said the US Geological Survey, which warned the disaster was likely to be widespread."High casualties and extensive damage are probable and the disaster is likely widespread," the USGS said, estimating the death toll would most likely range from 10,000 to 100,000.Vice President Delcy Rodriguez said the government was declaring a state of emergency and seeking funding from international organisations to support recovery efforts."We extend our condolences to those who have unfortunately suffered the loss of a family member," she said in a televised address, without giving a national death toll or injury count.The USGS's initial assessment estimate of up to 100,000 fatalities is preliminary and subject to revision as information emerges from affected areas.Officials reported collapsed buildings and rescue operations in several areas. Emergency crews worked through the evening in Caracas, where footage showed rescuers searching through the remains of damaged buildings while relatives waited for news of missing family members."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 and civil assistance," Interior Minister Diosdado Cabello said on state television.QuoteThere was a very loud crash. Things fell in the house. I've never experienced anything like it.Eyewitness Coro MartinezGustavo Duque, mayor of the Chacao district of Caracas, said several buildings had collapsed and that 18 people had been rescued from one structure. He urged residents to stay in open areas because of the risk of aftershocks."We're going to do everything we can to rescue the most people possible," he said.In Falcon state, Governor Victor Clark said 22 people had been injured and that authorities were searching for 15 missing adults.The earthquakes struck on a public holiday, sending residents rushing into the streets as buildings shook across the capital."As soon as it started, we began hearing people screaming," Astrid Ramirez, a 41-year-old publicist in western Caracas, was quoted as saying by Reuters. "Everyone was running down the stairs."Another resident, Coro Martinez, said objects fell around her home as the tremors hit."There was a very loud crash. Things fell in the house," she said. "I've never experienced anything like it."Hospitals in Caracas called in additional staff to help treat the injured, while authorities closed the country's main airport at Maiquetia because of damage. Classes were cancelled for the rest of the week as officials assessed the impact of the disaster.A tsunami warning issued after the earthquakes for Puerto Rico and the US and British Virgin Islands was later withdrawn.Venezuela lies in a seismically active zone where the Caribbean and South American tectonic plates meet.