La Guaira: Rescuers used heavy machinery and their bare hands on Friday in a race to save survivors of twin earthquakes in Venezuela that killed at least 235 people, hurt thousands and flattened scores of buildings.International rescuers and aid have begun arriving to help a nation struggling to respond two days after its strongest quake in well over a century struck west of Caracas, which prompted interim president Delcy Rodriguez to declare a state of emergency.Rubble from collapsed buildings had trapped more than 200 people under debris, National Assembly chief Jorge Rodriguez said Thursday.At the site of one of those flattened buildings, workers used sledgehammers to break the debris and called for "absolute silence" in order to hear survivors, AFP footage showed.Health Minister Carlos Alvarado reported on Thursday night that the death toll had risen to at least 235, with around 4,300 people injured.Rescue efforts have moved slowly, with bodies still visible under debris hours after the quakes, while time ran out for some of those who were trapped.Help has begun to arrive, with Salvadoran, Swiss and Mexican rescue teams already on the ground, as well as a senior American military official landing in Venezuela's capital Caracas to oversee US relief efforts.Nations around the world have pledged to send rescuers, money and aid, with the United States saying it was deploying two warships, transport planes and helicopters and mobilizing $150 million in aid.In the worst-hit state of La Guaira, north of Caracas, Amparo del Giudice dug with her bare hands at a huge mound of concrete in search of her son."It is a lot of rock, and with bare hands it is impossible," she said, exasperated and flailing at the rubble.Elsewhere, a young girl died after crying out for help for hours as onlookers listened helplessly, local residents told AFP."We need people... military personnel, to come and help so we can get her out," said resident Dani Rizo, 48.Earthquakes of similar magnitude claimed more than 200,000 lives in Haiti in January 2010 and 73,000 lives in Kashmir in October 2005 -- suggesting that the death toll in Venezuela was likely to rise.- Global rescue teams -The dead include foreigners, with nine Portuguese nationals, three Spaniards, two Brazilians, two Chinese nationals and one Italian-Venezuelan among those killed.Fifty-six Portuguese citizens and 99 Spaniards were missing or otherwise unaccounted for, according to their respective governments.Aerial photographs of La Guaira posted on social media showed one crumpled residential complex after another.A rescue worker, speaking off the record, told AFP conditions were precarious, with a shortage of trained personnel and significant technical limitations.Interim leader Rodriguez visited La Guaira on Thursday after the area was declared a "disaster zone."AFP reporters witnessed residents looting a local supermarket in the city.Venezuela's director of the International Rescue Committee, Nicole Kast, described the situation as catastrophic.Offers of support poured in from around the world, with Switzerland, Spain, France, Portugal and Mexico among those sending specialists and rescue teams.US Marine Corp Major General Kevin Jarrard has arrived in Caracas to "oversee Department of War support to Venezuela earthquake relief efforts," the US military's Southern Command said on Friday.US Secretary of State Marco Rubio earlier promised a "whole-of-government response. It'll be big, it'll be fast, and it'll be effective."- Airport closed -Washington is closely involved in oil-rich Venezuela after US forces ousted and arrested president Nicolas Maduro in January.China, India, Brazil and war-battered Iran all offered help, while Pope Leo XIV has sent an initial 100,000 euros (around $114,050) in aid.UN chief Antonio Guterres said he was "deeply saddened" by the disaster as the global body vowed to assist Venezuela.Threatening to complicate relief efforts, the capital's main international airport is in La Guaira and has been closed after suffering serious damage.Venezuelan opposition leader and Nobel Peace laureate Maria Corina Machado called for the release of "all political prisoners, both civilians and military personnel," saying they should reunite with loved ones as the country is mourning.Venezuela's northern coast sits on a boundary between the Caribbean and South American tectonic plates, but has not experienced a significant quake since 1997, when 73 people died. Another quake in 1967 killed 236 people.Wednesday's 7.5-magnitude earthquake was the most powerful since October 29, 1900, when a 7.7-magnitude tremor struck offshore.This week's quake was felt in neighboring Colombia, where residents in Bogota evacuated buildings as a precaution.Tremors were also reported in several cities in northern Brazil, according to the country's seismic monitoring network.