A strong earthquake jolted Mexico on Thursday, leaving at least two people dead as residents rushed into the streets of the capital in the middle of the night days after another powerful tremor. A woman died in Mexico City after falling down some stairs and hitting her head when the quake triggered early warning alarms, while a second victim in the capital suffered a heart attack, authorities said. The epicenter of the 6.9-magnitude earthquake was near the Pacific coast, 84 kilometers (52 miles) south of Coalcoman in the western state of Michoacan, the national seismological agency reported. The US Geological Survey (USGS) estimated the magnitude at 6.8. It was the strongest of more than 1,200 aftershocks from a magnitude 7.7 quake that struck the same area on Monday, the national seismological agency said. That tremor left two people dead in western Mexico, damaged several thousand buildings and sparked panic more than 400 kilometers away in Mexico City. The latest quake again triggered alarms in the capital shortly after 1:00 am (0600 GMT) and caused buildings to shake and sway. Many people quickly evacuated their homes when the alarms sounded, some still dressed in pajamas and carrying their pet dogs. “We had a 6.9 magnitude aftershock with an epicenter in Coalcoman,” President Andres Manuel Lopez Obrador said on Twitter. “Unfortunately, two people lost their lives in Mexico City,” he said, adding that there were no reports of victims in the western states of Michoacan, Colima and Jalisco.