The 5,400-metre volcano erupted with a plume of ash after shaking for several minutes early on Friday. Civil protection authorities reported that the cloud drifted west before turning back eat towards Puebla City.

Lying j37 miles southeast of Mexico city and its 18 million inhabitants it remains to be seen how the ash cloud will effect the megalopolis.

The volcano's activity has been reported as stable and there is no threat to populated areas. However, authorities have urged people to stay at least seven miles from the area and to await further information from Mexico's national disaster prevention agency.

The gas cloud is the largest in many years with authorities eagerly keeping watch over any potential change in activity.

Popocatepetl has had more than 15 major eruptions since the arrival of the Spanish in 1519.