AlHijjah 23, 1433, Nov 8, 2012, SPA -- Guatemala suffered its worst earthquake in decades late Wednesday with at least 48 people dead and 155 injured, dpa quoted authorities as saying. Twenty-three people remained buried under rubble, President Otto Perez Molina said. The quake hit most strongly in the south-western departments of San Marcos and Quetzaltenango near the border with Mexico, where it was also felt. Molina put the country on its highest alert, placed the military on standby and travelled by helicopter to San Marcos, where 40 of the victims died. In the San Marcos towns of San Pedro Sacatepequez, El Recuerdo, San Francisco, El Quetzal and other communities, numerous houses collapsed. In the neighbouring department of Quetzaltenango, adobe houses crumbled, killing four people and burying six others, rescuers working in the area said. Guatemala's seismological institute Insuvimeh said the earthquake had a magnitude of 7.2. The US Geological Survey said the quake measured 7.5 on the Richter scale. The epicentre was around 42 kilometres under the Pacific Ocean, 56 kilometres south-west of Retalhuleu, Guatemala, and 61 kilometres south-east of Suchiate in the southern Mexican state of Chiapas, The US-based agency said. Molina said the quake was the worst to hit his country since 1976 when a tremor killed 23,000 people. Wednesdays' quake caused panic in Guatemala City and led to the evacuation of high buildings on fears of aftershocks. The quake cut phone lines for a time. It was felt as far away as Mexico City although no damage was reported in Mexico. Three minutes later, an aftershock measuring 6.3 on the Richter scale caused panic and evacuations in central and southern Mexico. The aftershock's epicentre was 15 kilometres south-east of Rio Grande in the southern Mexican state of Oaxaca. It caused no damage. Thousands of people fled Mexico City buildings after the quakes, which rattled lamps and furniture. Helicopters flew over the city to assess potential damage, and the underground service was temporarily suspended. Mexico City was ravaged in 1985 by a quake that killed an estimated 10,000 people.