Residents on alert near Mexico volcano

"We can hear the roar of the volcano. Sometimes we can feel vibrations in our legs from its force," said Concepcion Perez, from the town of Xalitzintla in the central state of Puebla, 12 kilometres from the crater.

Authorities raised the alert level to "yellow phase three," extending a security radius around the towering, glacier-clad volcano 55 kilometres from the Mexican capital.

Officials in Puebla prepared temporary shelters in case of evacuations.

The National Disaster Prevention Centre said that activity within the volcano appeared to be diminishing, but they maintained the alert level.

Popocatepetl, Mexico's second highest peak, means "smoking mountain" in the indigenous Nahuatl language.