PEREIRA, Colombia — Rescue crews and civilians in Colombia painstakingly searched through rubble Tuesday in the hopes of finding survivors trapped under debris after a powerful earthquake left thousands missing in dozens of cities and towns. The 7.4 magnitude earthquake that hit western Colombia on Monday wreaked havoc, collapsing buildings, buckling roads, crushing cars and leaving devastated residents to console each other among the wreckage of their homes. Excavators and heavy machinery cleared heavy chunks of concrete, while buckets of rubble were passed hand-to-hand along a line of volunteers. Rescue crews and volunteers picked through flattened concrete buildings in affected cities, searching for signs of life. They raised their hands to call for silence when they thought they heard someone beneath the piles of debris. At least one woman was retrieved -- alive -- from the rubble. Colombian President Abelardo de la Espriella said the earthquake killed at least 181 people and left 2,595 more injured. He said at least 195 remained missing, but civilian-run databases suggest that number could be closer to 4,000. Crews race to find survivors Authorities said the deaths were concentrated in the cities of Cali, Pereira, Manizales and Quibdo, but local leaders and families worried about casualties and damage in rural areas, from where very little information has emerged. Aid agencies consider the first 48 to 72 hours crucial for retrieving people alive, though that threshold can be extended if they have access to food and water. De la Espriella said more than 1,000 homes were destroyed and yet more damaged. Standing near the remains of his brother’s collapsed apartment building in Pereira, Jairo Vargas said he made the 220-kilometre (135-mile) drive from Medellin, hoping to find his brother alive. “I’m absolutely certain he’s here. Absolutely certain,” Vargas said, adding that his brother’s car was still parked outside. But he fears his sibling did not survive. “The debris surrounding my brother is soft,” he said, as heavy machinery rumbled nearby. “It’s possible that it’s protecting him, but we can’t hear any noises anymore. I don’t know. I have little hope.” Colombia’s new president faces his first serious challenge The earthquake presents the first major test for first-time officeholder de la Espriella, who entered office just days before the natural disaster. The leader, who split the country in recent elections, now seeks to unite Colombia in its disaster response. That challenge was particularly notable in Choco, the region at the quake’s epicentre. It is one of Colombia’s poorest and most neglected regions, often beset by warring armed groups. Much of Choco is accessible only by boat, through the jungle or by airplane. Sterling Palacios, a religious and environmental leader in the region, said Choco’s capital and smaller communities along the Atrato River were devastated. Homes were reduced to rubble and aftershocks continued to rumble, terrifying residents who slept in the streets overnight. The Colombian Geological Service said it has documented more than 100 less powerful aftershocks since the initial quake. “There are towns where people have lost everything, where people have died, where homes have been destroyed,” he said. “We don’t have a full panorama of the damage, but we know it’s been massive.” De la Espriella traveled to Quibdo in Choco on Monday night where he announced he was mobilizing “the entire military and police apparatus,” as well as deploying engineers, rescue workers and search dogs. “Choco will never again be the `land of the forgotten,”' he said. Palacios said the government’s response has so far been “concentrated in the capital,” and that authorities were flying the wounded from Quibdo to hospitals in the city of Medellin. The biggest challenge, he said, remains towns in rural areas only reachable by boat -- journeys that can take hours or days. That response is also complicated by a toxic slate of armed groups warring for control who, during the COVID-19 pandemic, blocked healthcare workers from travelling to remote areas. “It’s a risk and it’s very difficult to predict” what could happen, he said, adding it could take weeks to fully assess the devastation. Astrid Suárez, Manuel Rueda and Megan Janetsky, The Associated Press Janetsky reported from Mexico City.