Aftershocks rattled Mexico over the weekend, as rescuers continued to search for survivors of Tuesday’s earthquake, the country’s deadliest in 32 years.

The latest tremor, of 5.9 magnitude, struck on Sunday off the west coast, with its epicentre 99 km southwest of Tonala, in Chiapas, the Pacific Tsunami Warning Center said. There were no immediate reports of significant damage.

Aftershocks on Saturday spread fear among the already traumatised population, and a plume of ash spewed from the Popocatepetl volcano in another reminder of the country’s volatile geology.

In the capital Mexico city, hopes of pulling people alive have faded by the hour.

Frustration with authorities has also grown among the thousands who lost their homes — now left sleeping in makeshift shelters or right on the street, anxiously holding pictures of their missing loved ones.

“We’ve been here since Tuesday. We haven’t received any news. We’ve been here for 24 hours and haven’t gotten any sleep. And no one has come to give us either good or bad news [...] I haven’t seen anybody pulled out of the rubble,” said Juan Pedro Jimenez, relative of a missing person in a collapsed building.

Tuesday’s 7.1-magnitude quake has killed at least 318 people and flattened dozens of buildings. The country’s deadliest since a 1985 tremor killed thousands, it was also the second major earthquake to strike Mexico this month.

Volunteers hailed as heroes

With Mexico facing a presidential election next year, the government’s response to the disaster is under close scrutiny.

Critics say the government’s reaction pales in comparison with the outpouring of volunteer support.

Thousands of volunteers have been working tirelessly to sift through the rubble, hand out food and comfort survivors and rescuers.

“We have received no help from authorities,” said Antonio Ramirez, who was conducting a survey of damaged homes in the historic Xochimilco district in the south of the capital.

“The help has come from ordinary people,” the 57-year-old retired teacher said. “Soldiers, instead of carrying picks and shovels, brought their guns.”

More aftershocks likely

Seeking to deflect the criticism, President Enrique Pena Nieto has visited the scene of the devastation, promised ongoing support to those affected, and urged Mexicans to turn their attention to rebuilding.

The latest tremor, of 5.9 magnitude, struck on Sunday off the west coast, with its epicenter 99 km (62 miles) south-southwest of Tonala, in Chiapas, the Pacific Tsunami Warning Center said. There were no immediate reports of significant damage.

Many more quakes are likely, warned Xyoli Perez Campos, director of Mexico’s National Seismological Service. “We have already recorded more than 4,300 aftershocks,” Campos said.

“So more aftershocks are to come. What we don’t know is if they are going to be of significant magnitude.”