MEXICO CITY (Reuters) - A magnitude 6.2 aftershock that shook Mexico on Saturday was blamed for five deaths, spreading fear among anxious residents reeling from a string of natural disasters and interrupting the search for survivors from a bigger tremor earlier this week.

The Popocatepetl volcano south of Mexico City sent a column of ash into the sky, capping an intense period of seismic activity including two powerful tremors this month that have killed more than 400 people and caused damage of up to $8 billion.

Mexico’s capital was shattered by Tuesday’s magnitude 7.1 quake that flattened dozens of buildings and killed at least 307 people. The government’s response to the disaster is under close scrutiny ahead of a presidential election next year.

Although the latest quake was not as destructive, fear is running high among the population. Terrified residents ran into the streets, where they crouched and prayed as earthquake sirens went off. Two women died of heart attacks as the ground shook, the city government said.

Tents were set up in different parts of the city where psychologists offered mental health support to survivors and rescuers traumatized by the natural disasters. Acts of solidarity came from all corners of Mexican society.

Tuesday’s quake hit on the anniversary of a 1985 tremor that, by some estimates, killed 10,000 people.

Roxana Trani, a 30-year-old banker, was one of the thousands of young Mexicans who turned to social media to find out how to help. She joined one of the aid collection centers that popped up in Mexico City and traveled to Puebla state in one of many convoys flooding from the city to more isolated communities.

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“I never understood why the people who suffered the ‘85 quake were so afraid of the slightest tremors. Now I get it,” Trani said.

“Being at a funeral and seeing all the pain that one minute caused has changed me,” she said.

FEAR OF COLLAPSE

Concern that the aftershock could cause further collapses paralyzed rescue efforts at a housing complex in the Tlalpan neighborhood of Mexico City, frustrating first responders who believed people were alive under the rubble.

By the evening, hard-hatted first responders were again digging for bodies or survivors in a dwindling number of rubble heaps. Their work barely skipped a beat elsewhere when earthquake alarms twice rang out across the city.

The United States Geological Survey said the latest quake was relatively shallow with an epicenter near Juchitan, a tropical region of Oaxaca state hard hit by a massive 8.1 magnitude tremor that struck on Sept. 7.

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Three people died in Oaxaca during Saturday’s tremor, including a man who was attacked by a swarm of wild bees, authorities said.

Mexico’s seismological authorities said it was an aftershock of the Sept. 7 tremor, which was the strongest to hit the country in 85 years and killed at least 98 people.

The Popocatepetl volcano, which is visible on a clear day to the approximately 20 million people who live in the Mexico City metropolitan region, spewed vapor and ash-filled gas after two small eruptions on Saturday.

Dozens of buildings were brought to the ground by Tuesday’s earthquake, while an army of trained rescuers helped by droves of volunteers frantically removed rubble in a day-and-night search for survivors.

Apartment buildings, offices, a school and a textile factory were among the structures flattened, leaving thousands homeless. The search had wound up at many sites by Saturday.

Officials said there could be some 30,000 badly damaged homes in the adjacent states of Morelos and Puebla. RMS, a risk modeling company, estimated economic losses of $4 billion to $8 billion.

Mexican volunteers, professionals and soldiers backed by teams from the United States and countries as far away as Japan and Chile have saved 69 people from the rubble after several days of searching. But in the past 48 hours rescuers have found more corpses than survivors, and frustration was mounting.

A government response seen as lacking in the disastrous 1985 temblor severely damaged the credibility of the ruling Institutional Revolutionary Party.

Mexico is now better prepared to deal with the aftermath of earthquakes, thanks to disaster planning, civic groups, a stringent building code and communication technology.

The government has run a massive search-and-rescue operation involving thousands of soldiers and police, but victims in outlying areas of the city and surrounding villages complained that aid has been slow to arrive.

“Here we have no help, everything is in the center (of the city),” said Justina Gonzalez, 55, a shopkeeper in the Xochimilco district in the far south of the city whose two-bedroom house fell down on Tuesday. She now lives in a tent and said neighbors were bringing her family food.

“We lost everything, we don’t even have a way to cook,” Gonzalez said.