Government experts said the 5,230-meter (17,159-foot) volcano was now calm after Saturday's three-minute explosion of the volcano resulting in a fine layer of ash being spread over the nearby city.

The volcano, located 60 kilometers (35 miles) southeast of the capital, was likely to undergo a series of similar explosions and emissions of ash "in the next few days and hours," the experts said.

On Saturday, a plume rose about three kilometres above Popocatepetl's crater before wind spread the ash over the city of 22 million residents.

Mexico City's chief official advised residents Sunday to cover their noses and mouths with a scarf or cloth to prevent it causing breathing problems.

People were told to keep calm in the wake of the eruption, to collect ash up in bags to avoid it blocking the city's drains, and to wash the ash off their cars to prevent it damaging paintwork.

Popocatepetl last underwent a period of violent activity in December 2000, forcing the evacuation of thousands of people who make their homes near its base.

TERRA.WIRE