A powerful 7.4-magnitude earthquake struck southern Mexico's Pacific coast on Tuesday, killing at least six people and seriously injuring many others. The powerful tremors caused damage to buildings hundreds of miles away in Mexico City. The fatalities were near the earthquake's epicentre in Oaxaca, a mountainous state known for its coffee, mescal and Spanish colonial architecture. In the coast resort town of La Crucecita, anxious residents stood outside their homes hours after the tremor as they feared deadly aftershocks. Houses were scarred by wide cracks across walls and residents sought to clear debris from the streets. About 200 houses in the area were hit, including 30 that were badly damaged, a local official said. "We lost everything in one moment to nature," said Vicente Romero, an owner of a stationary store whose house suffered structural damage. "This is our life's work." Rockfalls blocked winding mountain roads between the state capital of Oaxaca city and the coast. Rescue workers reported serious injuries to three people in the remote hill village of Santa Catarina Xanaguia, one state official said. Emergency workers battled for hours to reach the settlement, near the epicentre, where the earthquake brought down homes and parts of the mountainside, the official said. A clinic and old churches near the epicentre were severely damaged, images on social media showed. The dead included a worker from state oil company Pemex in Oaxaca, who fell from a height at the country's biggest oil refinery. The refinery was briefly closed after a fire. Miguel Candelaria, 30, was working at his computer in his family home in the Oaxaca town of Juchitan when the ground shook. He ran outside with relatives, but they stopped in the middle of the street as the pavement buckled and rocked. "We couldn't walk... the street was like chewing gum," said Candelaria, 30. Earthquakes of magnitudes 7 and above are deemed major and can cause widespread and heavy damage. Meanwhile, in Mexico City, buildings shook strongly and people ran into the streets when an early warning seismic alarm sounded. Two people were injured and more than 30 buildings in the capital suffered damage, officials said, including buildings still scarred from a 2017 earthquake that killed 355 people in the capital and the surrounding states. Water from rooftop pools or tanks cascaded down residential buildings in the city, and construction workers on the 56th story of a new residential tower clung to each other as it swayed, images on social media showed. The US Geological Survey said the epicentre of Tuesday's quake was 69km north-east of the town of Pochutla. It was shallow, only 26km below the earth's surface, which would have amplified the shaking. Near to the epicentre, Magdalena Castellanos Fermin was in the village of Santiago Astata when the "really intense" quake struck, sending large rocks tumbling down the hillside and alarming residents, she told Reuters. Eunice Pineda, a 26-year-old teacher in Juchitan, said the quake "was two minutes of torture", as she feared her house would collapse. But residents in one of Mexico's most seismically active regions have learned to "live one day at a time", she said. "We learn to appreciate, to treasure every moment."